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LinkOut Help [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2006-.

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LinkOut Help [Internet].

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Technical Information

Created: ; Last Update: August 7, 2013.

LinkOut is a service that allows users to link directly from PubMed and other NCBI databases to a wide range of information and services with the purpose of providing NCBI database users with on-target supplemental information to NCBI database records. LinkOut aims to facilitate access to relevant online resources to extend, clarify, and supplement information found in the NCBI databases.

Participating LinkOut providers, including publishers, aggregators, libraries, and other web resources, can display links to their sites on records from the NCBI databases.  A current list of LinkOut providers is available.

Resources Description
LinkOut requires two types of files, Identity and Resource files, to describe online resources.  These files are specified in the LinkOut DTD, and are provided by a participating provider.   These files include the necessary elements for the NCBI retrieval system to construct an appropriate URL to access specific resources. LinkOut DTD

Publishers and Other Full-Text Providers
Publishers and other full-text providers can use LinkOut to provide links from PubMed citations to their web-accessible full-text journals.  For publishers who supply their data to PubMed electronically and providers of free full text, an icon link will appear in PubMed’s Abstract format by default (more about default icons). Other providers should see Activating Icons for LinkOut Providers for information about promoting their icon to these display formats.

Additional information and file examples for publishers and other full-text providers are available in Information for Full-Text Providers.

Libraries
LinkOut provides libraries the means to link patrons from a PubMed citation directly to the full-text of an article from the library’s full-text provider. To do this, libraries must submit holdings information to LinkOut. Libraries should use the LinkOut Submission Utility to generate their LinkOut holdings. The holdings data should include those online journals that the library has a subscription to under a prior agreement. When a library submits their holdings data to NCBI, the providers of the holdings (publishers or aggregators) must be LinkOut participants, i.e. the providers have already submitted linking information for their online journals to NCBI.

Additional information is available in Information for Libraries.

Other Resources
LinkOut can also be used to provide links from NCBI databases to non-bibliographic Web resources, such as factual databases (i.e., organism-specific, taxonomy, structure and other databases), catalogs of research materials (clones, strains, probes, etc.), funding opportunities, clinical resources, research groups, and others.

Additional information and file examples are available in Information for Other Resource Providers.

LinkOut DTD

The LinkOut Document Type Definition (DTD) specifies the XML elements used in LinkOut files. The LinkOut DTD is available at LinkOut.DTD.

The URL for the DTD must be included in the prolog of a LinkOut file.

In the identity file, use:

<!DOCTYPE Provider "-//NLM//DTD LinkOut 1.0//EN" "http://www.ncbi.nlm.nih.gov/projects/linkout/doc/LinkOut.dtd">

In a resource file, use:

<!DOCTYPE LinkSet "-//NLM//DTD LinkOut 1.0//EN" "http://www.ncbi.nlm.nih.gov/projects/linkout/doc/LinkOut.dtd">

<!-- Typical usage:


        <!DOCTYPE LinkSet PUBLIC "-//NLM//DTD LinkOut//EN" "LinkOut.dtd">
        <LinkSet>
        ...
         </LinkSet>
            
         or:


         <!DOCTYPE Provider PUBLIC "-//NLM//DTD LinkOut//EN" "LinkOut.dtd">
         <Provider>
         ...
         </Provider>
    -->
<!--


   Rule based URL generation. In general, to build the
   URL both base and rule are required, where base is the
   HTTP base address, for example:
   
   http://www.sciencemag.org/cgi/content/full/


   and rule is in the following format:
&lo.vol;/&lo.iss;/&lo.page;


   LinkOut will replace the keywords in rule with the actual 
   value for a retrieved citation. Therefore, rule will be 
   translated into: 281/5384/1863
   
   The program will concatenate base with rule:


   http://www.sciencemag.org/cgi/content/full/281/5384/1863


The following keywords are supported for any database:


lo.id - Unique identifier (PMID, GI, TaxID, etc.)


For PubMed only: 


lo.pii   - Publisher Item Identifier.  Must be submitted by the publisher. For example, 6847, in the PubMed DTD this ID is an attribute of the ArticleId element. 
lo.doi   - Article DOI 
lo.issn  - Journal ISSN code 
lo.essn  - Journal Electronic ISSN code
lo.issnl - Journal ISSN code without the dash 
lo.jtit  - Journal title (MEDLINE abbreviation) 
lo.vol   - Volume 
lo.iss   - Issue 
lo.page  - First page 
lo.year  - Four digit year. For example, 1998 
lo.yr    - Last two digit of year. For example, 98; 00 
lo.yl    - Last digit of year. For example, for 1999 use 9; for 1990 use 0.
lo.eyear - Four digit year of electronic publication date. For example, 1998 
lo.eyr   - Last two digits of year of electronic publication date. For example, 98; 00 
lo.eyl   - Last digit of year of electronic publication date. For example, for 1999 
use 9; for 1990 use 0 
lo.month - The month. For example, September
lo.mon   - The 3 letter month abbreviation. For example, Sep 
lo.mo    - Two digit month. For example, 01; 12 
lo.emonth- The month of electronic publication date.  For example, September
lo.emon  - The 3 letter month abbreviation of electronic publication date. For 
example, Sep
lo.emo   - Two digit month of electronic publication date.
For example, 01;12 
lo.day   - Two digit day. For example, 01; 31 
lo.eday  - Two digit day of electronic publication date.  For example, 01; 31 
lo.auth  - First author 
lo.authln- Last name of the first author
lo.nlmid - NLM unique Identifier
lo.bookacc- Book accession number of a record
lo.bookname- Internal id for a book record
lo.elocationid – Electronic location Identifier of a record


For Sequence databases (Nucleotide, Protein, Structure, Genome):


lo.pacc  - Primary accession for sequences


For Taxonomy only:


lo.scientificname - Full scientific name.For example: "Homo sapiens neanderthalensis"
lo.genus – genus name
lo.species – species name
lo.subsp – subspecies name
For Gene only:


lo.genename – Gene name
lo.orgname – binomial, and strain when appropriate, from NCBI Taxonomy database
lo.taxid – unique identifier from NCBI Taxonomy database
lo.mimid – identifier(s) from Online Mendelian Inheritance in Man (OMIM)
-->
<!ENTITY lo.id                   "lo.id">
<!ENTITY lo.pii                  "lo.pii">
<!ENTITY lo.doi                  "lo.doi">
<!ENTITY lo.issn                 "lo.issn">
<!ENTITY lo.essn                 "lo.essn">
<!ENTITY lo.issnl                "lo.issnl">
<!ENTITY lo.jtit                 "lo.jtitle">
<!ENTITY lo.vol                  "lo.vol">
<!ENTITY lo.iss                  "lo.iss">
<!ENTITY lo.page                 "lo.page">
<!ENTITY lo.year                 "lo.year">
<!ENTITY lo.yr                   "lo.yr">
<!ENTITY lo.yl                   "lo.yl">
<!ENTITY lo.eyear                "lo.eyear">
<!ENTITY lo.eyr                  "lo.eyr">
<!ENTITY lo.eyl                  "lo.eyl">
<!ENTITY lo.month                "lo.month">
<!ENTITY lo.mon                  "lo.mon">
<!ENTITY lo.mo                   "lo.mo">
<!ENTITY lo.emonth               "lo.emonth">
<!ENTITY lo.emon                 "lo.emon">
<!ENTITY lo.emo                  "lo.emo">
<!ENTITY lo.day                  "lo.day">
<!ENTITY lo.eday                 "lo.eday">
<!ENTITY lo.auth                 "lo.auth">
<!ENTITY lo.authln               "lo.authln">
<!ENTITY lo.nlmid                "lo.nlmid">
<!ENTITY lo.bookacc              "lo.bookacc">
<!ENTITY lo.bookname             "lo.bookname">
<!ENTITY lo.elocationid          "lo.elocationid">
<!ENTITY lo.pacc                 "lo.pacc">
<!ENTITY lo.scientificname       "lo.scientificname">
<!ENTITY lo.genus                "lo.genus">
<!ENTITY lo.species              "lo.species">
<!ENTITY lo.subsp                "lo.subsp">
<!ENTITY lo.genename             "lo.genename">
<!ENTITY lo.orgname              "lo.orgname">
<!ENTITY lo.taxid                "lo.taxid">
<!ENTITY lo.mimid                "lo.mimid">


<!-- Entities for special characters -->


<!ENTITY reg        "&#174;" >
<!ENTITY copy       "&#169;">
<!ENTITY trade      "&#8482;">


<!-- internal DTD entities -->


<!ENTITY % url.data          "#PCDATA">
<!ENTITY % rule.data         "%url.data; | pad | apad | subs
                             | toupper | tolower | strip | normalize">
<!ENTITY % iso.lang.codes    "(DA|DE|EN|EL|ES|FR|IT|IW|JA|NL|NO|RU|SV|ZH)">
<!ELEMENT SubjectType        (#PCDATA)>


<!-- can be one of the following; see LinkOut SubjectTypes and Attributes at
http://www.ncbi.nlm.nih.gov/books/NBK3807/#files.Special_Elements_SubjectType 
for a description of these elements:


//CHEMICAL INFORMATION
        Biological Properties
        Chemical Libraries
        Imaging Agents
        Metabolism
        Molecular Interactions
        Physical Properties
        Reactions
        Theoretical Properties
        Toxicology
        Vendors


//EDUCATION
        conferences/meetings/workshops
        glossaries/dictionaries
        online tutorials/courses


//FUNDING SOURCES
        funding sources


//LITERATURE
        abstracts/indexes/summaries
        aggregators
        books
        individual online article
        images
        libraries
        patent databases
        publishers/providers


//MEDICAL
        clinical trials
        consumer health
        diagnostics
        disease organizations
        medical equipment and devices
        pharmacology
        treatment guidelines


//MOLECULAR BIOLOGY DATABASES
        DNA/protein sequence
        gene/protein/disease-specific
        gene expression
        locus-specific
        mapping
        organism-specific
        population/variation
        protein interactions/pathways
        structure
        taxonomy/phylogenetic


//RESEARCH MATERIALS
        clones/clone libraries
        culture/stock collections
        laboratory equipment
        oligonucleotides
        other reagents


//RESEARCHERS
        colleges/universities
        companies/research institutes
        directories
        individuals
        societies/associations


//TOOLS
        3D structure prediction/functional modeling
        primer design
        protein identification/characterization
        restriction mapping
        sequence screening/similarity/alignment
        sequence viewer
        translation
-->


<!ELEMENT Attribute   (#PCDATA)>
<!-- can be one of the following; see LinkOut SubjectTypes and Attributes at 
http://www.ncbi.nlm.nih.gov/books/NBK3807/#files.Special_Elements_Attribute


for a description of these elements:
//BARRIERS
        registration required
        subscription/membership/fee required


//OWNERSHIP
        author of URL
        publisher of information in URL


//Resource Form
        author manuscript
        electronic full-text
        full-text online
        full-text PDF
        full-text PostScript
        order form
        print collection       


//Administrative
        preference
-->
<!-- This is the top level element for Provider -->
<!ELEMENT Provider               (ProviderId, Name, NameAbbr, SubjectType?,
 Attribute*, Url*, IconUrl*, Brief?, ExclFileName*)>
<!ELEMENT ProviderId              (#PCDATA)>
<!ELEMENT Name                    (#PCDATA)>
<!ELEMENT NameAbbr                (#PCDATA)>
<!ELEMENT Url                     (%url.data;)>
<!ATTLIST Url              LNG    %iso.lang.codes;  "EN"  >
<!ELEMENT IconUrl                 (%url.data;)>
<!ATTLIST IconUrl          LNG    %iso.lang.codes;  "EN"  >
<!ELEMENT Brief                   (#PCDATA)>
<!ELEMENT ExclFileName                          (#PCDATA)>
<!ATTLIST ExclFileName          
                fieldname       (uid|query)             "uid"
                database        CDATA           #REQUIRED>


<!-- End of Provider group -->


<!ELEMENT LinkSet                 (Link+)>
<!ELEMENT Link                    (LinkId, ProviderId, IconUrl*,
(ObjectSelector|SubObjectSelector),(ObjectUrl+)>
<!ELEMENT LinkId                  (#PCDATA)>
<!ELEMENT ObjectSelector          (Database, ObjectList)>
<!ELEMENT Database                (#PCDATA)>
<!-- All NCBI databases may be configured to include LinkOut. Please write to
 linkout@ncbi.nlm.nih.gov for the current list of databases available for LinkOut -->
    
<!ELEMENT ObjectList              (FileName|(Query,ExclQuery*,ExclObjId*,ExclFileName*)|ObjId)+>
<!ELEMENT FileName                (#PCDATA)>
<!ATTLIST FileName                 fieldname   CDATA   #REQUIRED> 


<!ELEMENT Query                   (#PCDATA)>
<!ELEMENT ObjId                   (#PCDATA)>
<!ELEMENT ExclObjId               (#PCDATA)>


<!-- End of ObjectList group -->
<!-- End of ObjectSelector group -->


<!-- Libraries must use SubObjectSelector to refer to the sub providers -->
<!ELEMENT SubObjectSelector       (Database, SubProvider)>
<!ELEMENT SubProvider             (NameAbbr, (InclQuery|ExclQuery)*)>
<!ELEMENT InclQuery               (#PCDATA)>
<!ELEMENT ExclQuery               (#PCDATA)>
<!-- End of SubObjectSelector group -->


<!ELEMENT ObjectUrl              (((Base, (Rule|RuleToMany)?) | (Rule|RuleToMany)),
UrlName?, SubjectType?, Attribute*)>


<!ATTLIST ObjectUrl        LNG    %iso.lang.codes;  "EN" >


<!ELEMENT Base                    (%url.data;)>
<!ELEMENT pad                     (%rule.data;)*>
<!-- used to mark up strings that require padding to create
     fixed-length string attributes. --> 


<!ATTLIST pad   
        with                CDATA                  #REQUIRED
        width               CDATA                  #REQUIRED
        align               (left|right)            "right"> 
<!-- with a character to pad with (required)
     width result string size (required) (integer)
align the text should align to (left|right) (default:right)
     -->
     
<!ELEMENT apad                     (%rule.data;)*>
<!-- used to mark up strings that require padding to create 
     fixed-length string attributes. It skips all preceding 
     alpha characters before padding --> 


<!ATTLIST apad   
        with                CDATA                  #REQUIRED
        width               CDATA                  #REQUIRED
        align               (left|right)            "right"> 
<!-- with a character to pad with (required)width result string size (required) 
(integer)align the text should align to (left|right) (default:right)
     Examples:
      <apad with = "0" width = "6">E32</apad>  => "E00032"
      <apad with = "0" width = "6">640</apad>  => "000640"
     -->
<!ELEMENT subs                 (%rule.data;)*>
<!-- substitute one string for another in the element's content -->
<!ATTLIST subs  
        for                 CDATA                  #REQUIRED
        with                CDATA                 #REQUIRED>
<!-- for the string to replace with the string to substitute -->
     
<!ELEMENT toupper              (%rule.data;)*>
<!-- convert element content into upper case -->
<!ELEMENT tolower              (%rule.data;)*>
<!-- convert element content into lower case -->
<!ELEMENT strip                (%rule.data;)*>
<!-- strip off spaces/letters/digits in the element's content -->


<!ATTLIST strip  
 what   (spaces|letters|nondigits|digits)     #REQUIRED>


<!ELEMENT normalize            (%rule.data;)*>
<!-- are used for normalization of &lo.vol, &lo.iss; elements. Examples:
            "Pt 5"                  ==> "5"
            "3 Suppl"               ==> "3"
            "2A Pt 3"               ==> "2A"
            "10 Suppl 2 Pt 1"       ==> "10"
            "2/3"                   ==> "2"
      -->


<!ELEMENT Rule                    (%rule.data;)*>
<!ELEMENT UrlName                 (#PCDATA)>
<!ELEMENT RuleToMany              (Rule, Separator)>
<!ELEMENT Separator               (#PCDATA)>


<!-- End of ObjectUrl group -->
<!-- End of Link group -->
<!-- End of LinkSet group -->

Databases Available for Linking

Links can be made from the following NCBI databases to outside resources. When entering the database in the <Database> element, use the Db abbreviation, rather than the database name.

If you are interested in providing LinkOut links to other NCBI databases not listed in the above table, please write to vog.hin.mln.ibcn@ofni to express your interest to the relevant groups at NCBI.

Icons

Icons should:

  • Be 120 pixels wide x 30 pixels high or smaller.
  • Be in one of the following image formats: GIF, JPEG, or PNG
  • Identify the resource being linked. For libraries, this could be the library name and the format of the resource (full-text/print collection). For resource providers, this could be the name of the resource and/or the format or language in which the resource is being delivered.
  • If a journal or database resource is freely available, or free with a registration, the icon should have the text “Free.”
  • Look like an actionable button. The icon should have a border and a colored background. Icons and text should be easy to read and should not blend in to the PubMed display.
  • Not be animated.

The icon file name should use only letters from the English alphabet and numbers. Do not use special characters or spaces. Examples of file names are: libft.gif, libprint.gif, freeft.jpg, notfree.jpg.

Examples of icons are shown below.

Library icons

Image libicons.jpg

Other provider icons

Image files.G1.jpg

Identity File

The identity file contains the information about a provider that NCBI needs to list the provider in LinkOut. This file must be named providerinfo.xml; the file name is case sensitive.

Section Contents

Identity File Format

Note: The following format description shows the basic structure of an Identity file and includes all possible elements. Not all elements will be used in all files. Additional examples of Identity files are available for full-text providers, other resource providers, and libraries.

<?xml version="1.0"?>
<!DOCTYPE Provider PUBLIC "-//NLM//DTD LinkOut 1.0//EN"
"http://www.ncbi.nlm.nih.gov/projects/linkout/doc/LinkOut.dtd">
<Provider>
<ProviderId>ProviderId assigned by NCBI(required)</ProviderId>
   <Name>Name of Resource Provider or Library(required)</Name>
   <NameAbbr>NameAbbr assigned by NCBI(required)</NameAbbr>
   <SubjectType>SubjectType (optional)</SubjectType>
   <Attribute>Attribute (optional, repeatable)</Attribute>
   <Url>URL of provider’s website(optional, repeatable)</Url>
   <Brief>Short description of resource provider(optional)</Brief>
</Provider>

Identity File Prolog

The Prolog occurs once at the beginning of the file.

XML Declaration (required): <?xml version=”1.0”?>

Document Type Declaration (required): <!DOCTYPE Provider PUBLIC "-//NLM//DTD LinkOut 1.0//EN" "http://www.ncbi.nlm.nih.gov/projects/linkout/doc/LinkOut.dtd">

Identity File Elements

The following lists all elements that may be included in the Identity File. Not all elements will be used in every Identity file.

Provider(required): Root element of the file

ProviderId (required): A unique ID assigned by NCBI

Name (required): The full name of the resource provider or library. For libraries, this is the name of the library or institution; for other providers, this is the name of the organization.

NameAbbr (required): A short one word name for the resource provider or library. NameAbbr may only include alpha and numeric characters; spaces and special characters such as hyphens are not allowed. Because this element must be unique, NCBI reserves the right to adjust it as necessary. Resource providers who are submitting, or may submit, links on behalf of multiple publishers should select a neutral NameAbbr.

SubjectType (optional): SubjectTypes are used to display resources by Subject Category. SubjectTypes included in the identity file apply to all resources provided by a provider. See Special Elements: SubjectType for a list of SubjectTypes and descriptions. If no SubjectType is given, the SubjectType “miscellaneous” will be assigned automatically.

Attribute (optional, repeatable): Attributes describe resources independent of content and describe any ownership of the information that is being claimed by the individual or organization providing the link. Attributes included in the Identity file apply to all resources provided by a provider. See Special Elements: Attribute for the list of Attributes and descriptions.

Url (optional, repeatable): URL of the library or resource provider’s website, used in the LinkOut Providers list. Note: The URL may be different for different languages; see the LNG attribute in the LinkOut.DTD.

Brief (optional - displayed in My NCBI): Short description of the resource provider. Maximum is 255 characters.

The providerinfo.xml file is specified in the LinkOut DTD.

Resource File

The resource file describes the records the provider will link from and contains the information that LinkOut needs to generate links. Links described in the resource file should link directly to the resource; users should not have to perform any additional searching to access the resource after clicking the provider’s link.

Resource files which link to online full text must be submitted as XML files. Links to resources other than full text may be submitted as an XML file or as a simple text file.

Note: Resource files should be composed in a text editor, such as NotePad, rather than in a word processing program.

Resource File: XML

Files must have a file extension .xml; the file extension is case sensitive. The file name is assigned by the provider. File names should include alpha and numeric characters only. Spaces and special characters such as hyphens are not allowed. Examples of file names are journals.xml, journaltitle.xml, resourcename.xml

Note that Providers using <FileName> (see example below) need to supply a supplementary uid file, and the uid file name must be indicated in the element <FileName fieldname="uid">filename.uid</FileName>. This file would consist of a list of unique IDs (uid) of Entrez database records, and have the file extension .uid

File size may not exceed 20 MB. To help with file management, a provider may supply more than one resource file.

Section Contents

Resource File Format

Note: The following format description shows the basic structure of a Resource file and includes all possible elements. Not all elements will be used in all files. Additional examples of Resource files are available for full-text providers, providers submitting holdings on behalf of libraries, other resource providers, and libraries.

Using ObjectSelector (standard format)
<?xml version="1.0" ?>
<!DOCTYPE LinkSet PUBLIC "-//NLM//DTD LinkOut 1.0//EN"
"http://www.ncbi.nlm.nih.gov/projects/linkout/doc/LinkOut.dtd">
<LinkSet>
 <Link>
   <LinkId>Identifier assigned to link by provider(required)</LinkId>
   <ProviderId>ProviderId assigned by NCBI(required)</ProviderId>
   <IconUrl>URL of icon to be displayed on database records(required)</IconUrl>
   <ObjectSelector>
     <Database>NCBI database in which links will appear(required)</Database>
     <ObjectList>
        <Query>Search retrieving records to be linked(repeatable,
        required unless <ObjId> is specified</Query>
     </ObjectList>
   </ObjectSelector>
   <ObjectUrl>
     <Base>Stable portion of URL for provider’s resource(required)</Base>
     <Rule>Variable portion of URL for resource (required)</Rule>
     <SubjectType>SubjectType (optional)</SubjectType>
     <Attribute>Attribute (optional, repeatable)</Attribute>
     <UrlName>Short text string describing resource (optional)</UrlName>
   </ObjectUrl>
 </Link>
</LinkSet>
Using SubObjectSelector (for providers submitting links on behalf of libraries only)
<?xml version="1.0" ?>
<!DOCTYPE LinkSet PUBLIC "-//NLM//DTD LinkOut 1.0//EN"
"http://www.ncbi.nlm.nih.gov/projects/linkout/doc/LinkOut.dtd">
<LinkSet>
 <Link>
   <LinkId>Identifier assigned to link by provider(required)</LinkId>
   <ProviderId>ProviderId assigned by NCBI(required)</ProviderId>
   <IconUrl>URL of icon to be displayed on database records(required)</IconUrl>
   <SubObjectSelector>
     <Database>NCBI database in which links will appear(required)</Database>
     <SubProvider>
       <NameAbbr>LinkOut NameAbbr of the SubProvider(required)</NameAbbr>
       <InclQuery>Title Abbreviation or ISSN(required unless ExclQuery is
        specified, repeatable)</InclQuery>
     </SubProvider>
   </SubObjectSelector>
   <ObjectUrl>
     <Base>Stable portion of URL for provider’s resource(required)</Base>
     <Rule>Variable portion of URL for resource (required)</Rule>
     <SubjectType>SubjectType(optional)</SubjectType>
     <Attribute>Attribute (optional, repeatable)</Attribute>
     <UrlName>Link Resolver or Service Name</UrlName>
   </ObjectUrl>
 </Link>
</LinkSet>
Using FileName (requires a supplementary uid file)
<?xml version="1.0" ?>
<!DOCTYPE LinkSet PUBLIC "-//NLM//DTD LinkOut 1.0//EN"
"http://www.ncbi.nlm.nih.gov/projects/linkout/doc/LinkOut.dtd">
<LinkSet>
 <Link>
   <LinkId>Identifier assigned to link by provider(required)</LinkId>
   <ProviderId>ProviderId assigned by NCBI(required)</ProviderId>
   <ObjectSelector>
     <Database>NCBI database in which links will appear(required)</Database>
     <ObjectList>
        <FileName fieldname="uid">filename.uid (file with Entrez database uids)</FileName>   
     </ObjectList>
   </ObjectSelector>
   <ObjectUrl>
     <Base>Stable portion of URL for provider’s resource(required)</Base>
     <Rule>Variable portion of URL for resource (required)</Rule>
     <SubjectType>SubjectType</SubjectType>
     <Attribute>Attribute (optional, repeatable)</Attribute>
     <UrlName>Short text string describing resource (optional)</UrlName>
   </ObjectUrl>
 </Link>
</LinkSet>

Resource File Prolog

The Prolog occurs once at the beginning of the file.

XML Declaration (optional): <?xml version=”1.0”?> (required)

Document Type Declaration (required): <!DOCTYPE LinkSet PUBLIC "-//NLM//DTD LinkOut 1.0//EN" "http://www.ncbi.nlm.nih.gov/projects/linkout/doc/LinkOut.

dtd"
[ <!ENTITY icon.url "http://www.goodpublisher.com/icon/goodpublisher.jpg">
<!ENTITY base.url "http://www.goodmedical.org/cgi/content/" > ]>

The Entity Declaration, included in the Document Type Declaration, is optional. ENTITY may be specified to be used in the body of the file.  In the above example, ENTITY icon.url is defined with the value “http://www.goodmedical.org/images/icon.gif”, and ENTITY base.url is defined with the value “http://www.goodmedical.org/cgi/content/".

Once an ENTITY is defined in the Prolog, it can be used in the holding file by placing the ENTITY name between an ampersand (&) and semicolon (;).  This alleviates the need to replicate long, textual data. In the above example, '&icon.url;' is used to represent the URL of the provider icon. Using ENTITY icon.url will make it easier to change the icon URL if necessary, because it will only need to be changed in one place.

Resource File Elements

The following lists all elements that may be included in the Resource file. Not all elements will be used in every Resource file.

LinkSet (required): Root element of the holdings file

Link (required,repeatable): An element that describes a specific set of resources grouped together by access characteristics or for convenience. A holdings file can have multiple Link elements. Resources that can be accessed via a single URL Rule are usually grouped in one Link. To help with file management, you may choose to put holdings in different Link elements, even if the same URL Rule applies to all holdings.

LinkId (required): An identifier assigned by a participating provider for its own reference. The LinkId can be any alpha-numeric string. Each Link within a LinkSet or file must have a unique LinkId.

ProviderId (required): The identifier number assigned to the publisher by NCBI and listed in the providerinfo.xml file.

IconUrl (optional, repeatable): The URL of the icon that will be displayed on the database records described within the Link element. The icon should meet the specifications described in Icons. IconUrl is repeatable as defined in the LinkOut DTD. However, this functionality is not implemented. Icons appear only in PubMed.

ObjectSelector (required unless SubObjectSelector is specified): An element containing other sub-elements in which a provider will specify which database records are being linked from by a Link element.

SubObjectSelector (required unless ObjectSelector is specified): An element containing other sub-elements in which journals and full-text providers for those journals are specified. For use by libraries and providers submitting information on behalf of libraries.

Database (required): A sub-element of ObjectSelector or SubObjectSelector that specifies the NCBI database in which the links will appear.

ObjectList (required if ObjectSelector is specified, repeatable): A sub-element of Object Selector, containing Query or ObjId elements, that specifies which database records the URL(s) defined in ObjectUrl will link from. Note that all components of a query have to be valid for the query to be used for linking.

SubProvider (required if SubObjectSelector is specified): A sub-element of SubObjectSelector. SubProvider contains NameAbbr and InclQuery elements. This element describes the publishers or full-text providers with whom a library has a pre-arranged access agreement.

Query (required sub-element of ObjectList unless ObjId is specified, repeatable): A sub-element of ObjectList that contains a valid search used to select the records in the database specified in Database that will be linked from.

ObjId (required sub-element of ObjectList unless Query is specified, repeatable): A sub-element of ObjectList that contains the Unique Identifier for a database record.

FileName (required sub-element of ObjectList. A supplementary uid file is required): A sub-element of ObjectList that contains the file name for the supplementary uid file. For example <FileName fieldname="uid">filename.uid</FileName>.

InclQuery (required sub-element of SubProvider unless ExclQuer is specified, repeatable): A sub-element of SubProvider that includes a journal supplied by the SubProvider as a part of the online journal holdings of a library.  Use the MEDLINE Journal Title Abbreviation or ISSN. Both are available in the list of LinkOut Journals.

ExclQuery (required sub-element of SubProvider unless InclQuery is specified, repeatable): A sub-element of SubProvider that excludes a journal supplied by the SubProvider from the online journal holdings of a library.  Use the MEDLINE Journal Title Abbreviation or ISSN. Both are available in the list of LinkOut Journals.

ObjectUrl (required): An element that describes the information necessary for the NCBI systems to construct URLs to access the full-text for database records specified in the ObjectList. ObjectUrl contains two required sub-elements, Base and Rule.

Base (required): A sub-element of ObjectUrl that is the stable portion of the URL for the provider’s web-accessible resource. This can be defined as an ENTITY in the Entity Declaration. No LinkOut entities can be used in this element.

Rule (required): A sub-element of ObjectUrl. The Rule will be concatenated with the Base to create a valid URL when a record is retrieved from a search. Allowable Keywords in the Rule will be translated into the correct values for the specific database record. The Rule is based on the provider’s specifications for access to the resource. Links should point directly to the resource. LinkOut entities can be used in this element.

SubjectType (optional): SubjectTypes are used to display resources by subject category. SubjectTypes apply to all resources identified within a <Link>. See Special Elements: SubjectType for the list of SubjectTypes and descriptions. If no SubjectType is given, the resource will be displayed under the category “Miscellaneous”. If a SubjectType is provided in the Identity file, then it should not be included in the Resource file(s).

Attribute (optional, repeatable): Attributes describe resources independent of content and describe any ownership of the information that is being claimed by the individual or organization providing the link. Attributes apply to all resources identified within a <Link>. See Special Elements: Attribute for the list of Attributes and descriptions.

UrlName (optional): A short text string that describes a resource. UrlName is typically used when the allowed SubjectTypes and Attributes cannot meet the needs of a provider.

The resource file is specified in the LinkOut DTD.

Resource File: Simple Text

Files linking to resources other than full text may be submitted as a simple text file, rather than an XML file.

Files must have a file extension .ft; the file extension is case sensitive. The file name is assigned by the provider. File names may only include alpha and numeric characters, spaces and special characters such as hyphens are not allowed. Example file names might be resources.ft, resourcename.ft.

File size may not exceed 10 MB. To help with file management, a provider may supply more than one resource file.

Files submitted as text files will be translated into valid XML by LinkOut. Translated files will conform to the LinkOut DTD.

File Syntax

The file consists of blocks separated by comment lines beginning with "-":
 

------ lines starting with "-" are comments -----
------ information in the first block is global-----
prid:   [required] 
dbase:  [required] 
stype:  [optional] 
attr:   [optional]
!base:  [optional] 


------ 
linkid: [required - LinkOut will add a suffix to make sure it is unique] 
uids:   [required if query is not present] 
query:  [required if uids is not present] 
base:   [required] 
rule:   [required] 
icon:   [optional] 
name:   [optional] 
stype:  [optional] 
attr:   [optional] 
------ 

The first block holds global information that will be used throughout the file.

prid:   LinkOut Provider ID

dbase:   NCBI database that will be hosting the links, e.g., pubmed, nucleotide, taxonomy

stype:   SubjectType. See Special Elements: SubjectType for all available SubjectTypes.

attr:    Attribute. See Special Elements: Attribute for all available Attributes.

Each subsequent block specifies a link to the provider’s resource. This has two basic parts, a search query and a URL pointing back to the provider's site. Each query will be evaluated, and any database records that are retrieved will be assigned a link to the URL specified by the provider. An example of simple blocks is shown below.

----- 
query: <species1> [name] 
rule:  <http://...my_species1_page.html> 
----- 
query: <species2> [name] 
rule:  <http://...my_species2_page.html> 
-----  

Any valid search query may be used to select records. See Entrez Help for information on constructing search queries. Each query should appear on a single query line. Multiple query lines in one block will be OR-ed together. The following two link descriptions are equivalent:

Link Description 1:

-----
query: <species1> [name] OR <species2> [name] 
rule:  <http://...my_species1or2_page.html> 
----- 

Link Description 2:

----- 
query: <species1> [name] 
query: <species2> [name] 
rule:  <http://...my_species1or2_page.html> 
----- 

Objects in each NCBI database are indexed by a numerical unique identifier. For example, taxid in taxonomy, gi in nucleotide and protein, pmid in PubMed. You can specify the database records you would like to link from by listing them directly with the uids: line.

Link description with uids:

--- separate unique identifiers (UIDs) with a blank space.---
---Each new line of UIDs should start have the “uids” label---
uids: 123456 123469 3847559 
uids: 4755983 2197866
rule:  <http://...my_species1or2_page.html> 
----- 

The optional fields allow you to customize your links in several ways.

icon:   URL of an icon file that you would like to represent your link and resources. Only applicable to links in PubMed.

name:   Additional description about the link.

stype:   SubjectType. See Special Elements: SubjectType for all available SubjectTypes.

attr:   Attribute. See Special Elements: Attribute for all available Attributes.

Special Elements: SubjectType

The <SubjectType>, <Attribute>, and <UrlName> elements are used to organize and describe resources in the database displays and to facilitate access to these resources by defining them as groups.

SubjectType is used to group resources in the LinkOut Display, making it easier to browse through available LinkOut resources. In most cases, resources are grouped by Subject Category (described below).

Only one SubjectType should be applied to each Link. If no SubjectType is specified for a Link, it will be displayed under the heading "Miscellaneous".

SubjectTypes are also used in My NCBI, allowing users to display records with links to resources from a specific SubjectType or Subject Category as a filter, and to activate icons for these links.

SubjectType can be used in searches to retrieve records with links to resources from a specific SubjectType.

To do this, enter the following the in the search box.

losubjtSubjectTypeName [sb]
Replace SubjectTypeName with the SubjectType name from the list below.

This filter can be used as a part of any NCBI database search.

SubjectType Categories

SubjectTypes are grouped into the following categories:

Note: Category headings CANNOT be used in the the <SubjectType> element.

Chemical Information

biological properties: Information about chemicals with biological activity.

chemical libraries: Link to libraries of chemicals provided by depositors, for example screening centers.

imaging agents: Information on radionuclide-containing chemicals which bind to specific sites/molecules and help to detect motion/binding.

metabolism: Information about chemicals participating in metabolism.

molecular interactions: Information about chemicals which interact or bind to other molecules (for example, protein-protein or small molecule-protein interactions)

physical properties: Information about chemicals with determined physical properties.

reactions: Information on chemicals which used as reactants/products/intermediates/catalysts.

theoretical properties: Information about chemicals with calculated properties.

toxicology: Information on chemicals investigated for their toxic effect.

vendors: Information from commercial distributors of chemicals.

Education

These SubjectTypes describe links from NCBI database records to resources offering educational content, as well as those providing information about educational opportunities.

conferences/meetings/workshops: Resources offering announcements of, or information on upcoming scientific conferences, meetings, and workshops relevant to the subjects of specific database records.

glossaries/dictionaries: Resources offering glossaries or dictionaries of technical terminology or other specialized vocabularies used in research relevant to specific database records.

online tutorials/courses: Resources offering information about or providing Web-based primers, tutorials, or courses on specialized areas of research relevant to specific database records.

Funding Sources

The SubjectType in this category describes links to resources within information on funding for research.

funding sources: Resources providing information on locating, applying for, or obtaining funding for particular areas of research relevant to the subjects of specific database records.

Literature

These SubjectTypes describe links to literature databases and resources from NCBI databases records (typically PubMed records).

SubjectTypes under the "Literature" category appear in the LinkOut Display as follows:

  • Resources from "aggregators", "individual online article", "publishers/providers" are grouped under the heading "Full Text Sources".
  • Links with SubjectType "libraries" are displayed under the heading "Libraries".
  • The SubjectTypes: "author profiles", "books", "document delivery", "images", and "supplemental materials" are displayed under the heading "Other Literature Sources".

aggregators: Services that provide a single point of online access to multiple full-text publications cited in NCBI database records. "aggregators" are differentiated from "publishers/providers" (see below) by their aggregation of online access to the publications of multiple publishers and/or providers. See LinkOut: Information for Full-Text Providers for details on LinkOut and full-text.

author profiles: Resources offering biographical information and/or research interest of authors of a PubMed citation

books: Links to relevant information in a book.

commentaries/discussion: Links to commentaries or discussion to extend/continue the topic discussed in the article cited in a PubMed citation.

document delivery: Links to vendors that deliver electronic or print copies of documents to users.

images: Links to online images from the NCBI database records that they are relevant to or referenced by.

individual online article: Links from NCBI database records to individual online copies of the publications that they reference (i.e., a link from a PubMed record to a copy of a research article that the author has made available on her/his personal website or on a depository).

libraries: Links to the online full text and print holdings of a library. Links to online holdings will point directly to full-text articles; links to print holdings will point to a record of the library’s print holdings.

patent databases: Links to patent database records from PubMed citations of publications discussing patented products (including proteins and DNA sequences) or processes, or from relevant NCBI database records.

publishers/providers: Links to online full-text articles offered by publishers or their agents.

supplemental materials: Links to the materials directly supporting the research discussed in the cited article, including data sets from experiments/studies accessory graphics, images, sound, and multimedia files related to the article.

Medical

These SubjectTypes describe links from NCBI database records to relevant online medical resources.

clinical trials: Links from NCBI database records to resources providing information about relevant ongoing and upcoming clinical trials, including information on locating, applying to, or participating in clinical trials.

consumer health: Links from NCBI database records to relevant resources or materials intended to educate or inform the general public about particular health topics or issues.

diagnostics: Resources providing information on the signs, symptoms and diagnosis of diseases, syndromes, or conditions relevant to specific NCBI database records.

disease organizations: Institutions, groups, or other organizations whose work is focused on the research of particular diseases or conditions, or that offer information, support, and/or other resources to people suffering from particular diseases or conditions, linked from relevant NCBI database records.

medical equipment and devices: Organizations or companies providing medical equipment or other medical devices relevant to specific NCBI database records.

pharmacology: Resources providing information on the pharmacological aspects of substances relevant to specific NCBI database records.

treatment guidelines: Resources offering treatment guidelines or information on treatment guidelines for particular diseases, syndromes, or conditions relevant to specific NCBI database records.

Molecular Biology Databases

These SubjectTypes describe links from NCBI database records to corresponding or related records in other online molecular biology databases.

DNA/protein sequence: Databases providing nucleotide or amino acid sequence data.

gene/protein/disease-specific: Databases providing data specific to particular genes, proteins, diseases, syndromes, or conditions.

gene expression: Databases providing data on gene expression (e.g., RNA transcription, knockouts).

locus-specific: Databases, often described as LSDB, focusing on a single gene or a small family of genes.

mapping: Databases providing chromosomal mapping data, such as sequence tagged site (STS) mapping.

meta-databases: Databases that draw and/or synthesize information from other databases and extend or add value to the original information.

organism-specific: Databases providing data specific to a particular organism or group of organisms.

population/variation: Databases providing data on sequence variation within particular populations, including mutations or other polymorphisms.

protein interactions/pathways: Databases that describe molecular interactions and/or biological pathways.

structure: Databases providing structural or pattern data, such three-dimensional protein structures, chemical structures, or two-dimensional electrophoresis patterns.

taxonomy/phylogenetic: Databases providing data on organism taxonomy, phylogenetic trees and relationships, or biodiversity.

Research Materials

These SubjectTypes describe links to relevant research material suppliers from NCBI database records that discuss the use of these materials.

clones/clone libraries: Suppliers providing DNA clones and clone libraries (e.g., DNA, cDNA).

culture/stock collections: Suppliers providing cell cultures.

herbarium/museum collections: Curated plant/animal specimen collections

laboratory equipment: Suppliers providing laboratory equipment.

oligonucleotides: Suppliers providing equipment, materials, and reagents used in researching oligonucleotides.

other reagents: Suppliers providing other reagents not described by the SubjectTypes above.

Researchers

These SubjectTypes describe links from NCBI database records to the individuals or organizations that conducted or supported the research cited therein.

colleges/universities: Colleges, universities or other academic institutions that have conducted or supported research cited in NCBI database records.

companies/research institutes: Private companies or research institutions that have conducted or supported research cited in NCBI database records.

directories: Links to the directory entries of individuals or organizations from NCBI database records that cite research conducted or supported by those individuals or organizations.

individuals: The web pages of individuals who have conducted research cited in NCBI database records.

societies/associations: Societies or organizations that have conducted or supported research cited in NCBI database records.

Tools

These SubjectTypes describe links to research tools, utilities or other software from NCBI database records citing research that discusses or requires the use of these tools.

3D structure prediction/functional modeling: Tools used in predicting the three-dimensional structure of proteins or in modeling protein function.

primer design: Tools used in the design of nucleotide primer sequences for use in polymerase chain reactions.

protein identification/characterization: Tools used in the identification, annotation, characterization, or other description of proteins.

restriction mapping: Tools used in the mapping of restriction enzyme cutting sites.

sequence screening/similarity/alignment: Tools used in screening, comparing, matching, and alignment of sequences.

sequence viewer: Tools used in creating visual representations of nucleotide or amino acid sequences.

translation: Tools used in the translation of sequences or of sequence file formats.

Special Elements: Attribute

The <SubjectType>, <Attribute>, and <UrlName> elements are used to organize and describe resources in the NCBI database displays and to facilitate access to these resources by defining them as groups.

The Attribute element is used to provide information about the resource itself, independent of content. It describes the format, barriers to access, and the ownership (if any) of the resources being linked. On the basis of information provided by Attribute, users can make an informed choice from a list of LinkOut resources available. For example, they will know if a resource is free before clicking the link.

Attributes can be used in database searches to retrieve records with links to resources with a specific Attribute.

To do this, enter the following the in the search box.

loattrAttributeName [sb]
Replace AttributeName with the Attribute name from the list below.

This filter can be used as a part of any NCBI database search.

Special aliases are also available for these searches:

Full text [sb]

Free full text [sb]

For each resource, the provider should select all Attribute values from the list below that apply and include them in the appropriate LinkOut files.

Attribute Categories

Attributes are grouped in the following categories:

Barriers
Ownership
Resource Form
Miscellaneous

Barriers

These Attributes describe barriers to accessing the information being linked to from a database record.

registration required: A free registration is required to access the information being linked. If any expense is involved, please use the Attribute “subscription/membership/fee required”. Citations with this Attribute will be marked as “Registration required” in the LinkOut links.

subscription/membership/fee required: Membership in an organization, a subscription, or some other fee or expense is required to obtain access to the information being linked.

If no Barrier Attributes are used, citations will be marked as “Free” in the LinkOut links.

Ownership

These Attributes describe any ownership of the information that is being linked claimed by the individual or organization providing the link.

author of URL: The individual or organization providing a link is the author of the information that is being linked.

publisher of information in URL: The individual or organization providing a link is the publisher of the information that is being linked.

Resource Form

These Attributes describe the form of the documents being linked from NCBI database records.

author manuscript: Final, peer reviewed manuscripts that have been accepted for publication. These manuscripts are typically posted on a journal website or at PubMed Central.

electronic full-text: Online full-text holdings of a library.

full-text online: Full-text documents that are in text, HTML, word processor, or other formats (besides PDF or PostScript).

full-text PDF: Full-text documents that are in Adobe Portable Document Format (PDF).

full-text PostScript: Full-text documents that are in PostScript format.

order form: Order form for the resources mentioned in the database record, e.g. clones.

print collection: Print collection of a library.

Miscellaneous

Attribute not included in other categories:

preference: When duplicate URLs are submitted for the same database record but different IconUrl, SubjectType, and/or Attributes are assigned, use preference to indicate which link should be displayed. See Duplicate Links for details.
When a provider submits multiple, unique, URLs for a PubMed record, the provider should use preference to indicate which URL should be linked through their icon in PubMed. See Multiple Links for details.

Special Elements: UrlName

UrlName is a short text string used to describe a resource. If possible, <SubjectType> and <Attribute> should be used, rather than UrlName. UrlName should be used only when the allowed terms in the SubjectType and Attribute lists do not suffice to describe the resource. UrlName is not searchable.

When UrlName is used, it will appear in the LinkOut Display. In the example below from the Gene database LinkOut display, the two providers Kyoto Encyclopedia of Genes and Genomes and TaqMan have used UrlName to provide additional information about the resource being linked. The link appears as the description given in UrlName. The first provider has not used UrlName, so the link appears as the resource name.

Image files.G2.jpg

Allowable Rule Keywords

As in all XML files, entities can be defined and used in LinkOut files to facilitate file construction.

There are a number of pre-defined Linkout entities (Allowable Rule Keywords) in the LinkOut DTD. When an entity is used in the <Rule> element, the NCBI system will replace the entity with the corresponding value from each NCBI database record when constructing the URL specified in your <Rule>. Note that LinkOut entities cannot be used in the <Base> element or other elements in a LinkOut file.

The following is a list of entities and the values with which they will be substituted:

EntityCorresponding value from NCBI database record
&lo.id;Unique identifier (PMID, GI, TaxID, etc.)

For PubMed only:

EntityCorresponding value from NCBI database record
&lo.auth;First Author. Example: Smith JE.
&lo.authln;First Author Last Name. Example: Smith.
&lo.day;Two-digit day of the publication date. Example: 01; 31.
&lo.doi;Article DOI. Must be submitted by Publisher.
&lo.eday;Two-digit day of electronic publication date. Example: 01; 31.
&lo.emo;Two-digit month of electronic publication date. Example: 01; 12.
&lo.emon;Three-letter month abbreviation of electronic publication date. Example: Sep.
&lo.emonth;Month of electronic publication date. Example: September.
&lo.eyear;Four-digit year of electronic publication date. Example: 1998.
&lo.eyl;Last digit of year of the electronic publication date. Example: 1999 =9.
&lo.eyr;Last two digits of year of electronic publication date. Example: 98; 00.
&lo.essn;Journal electronic ISSN code.
&lo.iss;Journal issue.
&lo.issn;Journal print ISSN code.
&lo.issnl;Journal print ISSN code with the dash stripped.
&lo.jtit;Journal title (NLM’s Title Abbreviation).
&lo.mo;Two-digit month abbreviation of the publication date. Example: 01.
&lo.mon;Three-letter month abbreviation of the publication date. Example: Sep.
&lo.month;Month of the publication date. Example: September.
&lo.otit;Article title.
&lo.page;First page.
&lo.pii;Publisher Item Identificator. Must be submitted by Publisher.
&lo.vol;Journal volume.
&lo.year;Four-digit year of the publication date. Example: 1998.
&lo.yl;Last digit of year of the publication date. Example: 1999 =9.
&lo.yr;Last two digits of year of the publication date. Example: 98.

For Sequence databases (Nucleotide, Protein, Structure, Genome):

EntityCorresponding value from NCBI database record
&lo.pacc;Primary accession for sequences.

For Taxonomy only:

EntityCorresponding value from NCBI database record
&lo.scientificname;Scientific name. Example: "Homo sapiens neanderthalensis”

For UniGene only:

EntityCorresponding value from NCBI database record
&lo.clusterid;Cluster Id.

Special Characters

XML requires certain special characters to be encoded in the files. When using the following characters in LinkOut files, except in LinkOut entities, please encode them as shown.

CharacterXML Encoding
&&amp;
<&lt;
>&gt;
©&copy;
®&reg;
&trade;

LinkOut does not support Unicode (UTF-8).

Do not use ASCII encoding in LinkOut files.

Transferring Files via FTP

Providers must write to vog.hin.mln.ibcn@tuoknil to apply for inclusion in LinkOut before submitting files.

LinkOut files are submitted to NCBI via FTP to the host: ftp-private.ncbi.nlm.nih.gov. The following file name conventions apply:

  • File names may include alpha and numeric characters only. Spaces and special characters such as hyphens are not allowed.
  • Identity and Resource files must have the file extension “.xml”. The exception is resource files submitted as a simple text file.
  • Identity files must be named “providerinfo.xml”.

File Placement

  • Resource provider files (both full-text and other providers) are placed in the “holdings” directory of the FTP account.
  • Files submitted on behalf of libraries by full-text providers are placed in the “users “ directory.
  • Files submitted by libraries are placed in the “collection” directory
  • “.doi” or “pii” files are placed in the “pid” directory .

Files placed in an incorrect directory will not be processed.

How to FTP

From a standard ftp client:

1.

At a command prompt type: ftp-private.ncbi.nlm.nih.gov and press enter.

2.

Type your login name at the login prompt and press enter. (See how to obtain ftp account from NCBI.)

3.

Type your password at the password prompt and press enter.

4.

You should now be logged into the ftp server. If you receive an error message, check your login information, type 'bye' followed by enter, and retry steps 1-3.

5.

Type 'bin' and press enter. This changes your ftp server to BINARY mode.

6.

Type ‘cd [directory, i.e. holdings, users]’ and press enter. This changes your current directory.

7.

Type the 'put' command, followed by your pathname or drive and filename and press enter.  (For example, 'put C:\filename' or 'put /home/testfiles/journalv6n3'.)

8.

Type 'dir' and press enter to display the files in the current directory.

9.

Type 'bye' to disconnect from the server and close the ftp session.

From a browser window:

1.

Enter: ftp://ftp-private.ncbi.nlm.nih.gov in your browser’s “Address” field and press enter.

2.

From the file pull-down menu, choose "Login As".

3.

Type in your username and password in the dialog box. The screen will display your directory with subdirectory folders inside.

4.

Open the folder into which you will be depositing files.

5.

Add files in the selected directory

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