These Tagging Guidelines describe PubMed Central's preferred XML tagging style for journal article submissions in the NLM Journal Publishing DTD or the NISO JATS Journal Publishing DTD. Users of this document should have an understanding of XML and a basic familiarity with the DTD.

The Guidelines contain style rules for data tagged in versions 1.3, 1.2, 1.1, and 1.0 of the NISO JATS Journal Publishing DTD, and versions 3.0 and 2.3 of the NLM Journal Publishing DTD. Where style rules differ among the versions, the rules are displayed in colored boxes to distinguish them. The "Show/Hide Version Rules" controls on the left navigation menu allow you to show or hide all rules for any version. Additionally, in each item where the rules differ, there are links to show or hide the version-specific rules for that item.

Tagging Guidelines Organization

The Tagging Guidelines are described in three separate sections. Each section describes separate rules that must be followed when creating PMC-style compliant XML. Many of the rules are related and often contain links to other sections.

In addition to these three sections, all updates to the Tagging Guidelines are documented in the Update History.

General Tagging Practice

These style rules apply to structured data tagging at a very broad level and include formatted text, math, and special characters.

Document Objects

This section describes specific parts of XML documents like figures and author/affiliation relationships. It references specific elements and includes examples of XML tagging.


This section describes style rules for specific XML elements and their attributes. Only elements for which PMC has a style rule are described in this section. Refer to the Tag Library for descriptions of all elements available in the DTD.

Occasionally the Tagging Guidelines and the Tag Libraries have different tagging instructions or examples. In those cases, tag submissions to PMC according to the examples in the Tagging Guidelines which always describe PMC’s preferred style.

Tools and Resources

PMC has provided the following tools and resources for use with the Tagging Guidelines.

Tagging Guidelines Email List

The Tagging Guidelines and Style Checker are updated periodically, in an effort to make the PMC archive more robust, improve the quality of the XML submitted, and ensure stability for future retrieval. PubMed Central announces these periodic changes through our pmc-tagging-guidelines email list. To subscribe, please visit

Style Checker

This web-based tool provides a detailed report of all items in an XML file that do not comply with PMC style. The report will list items as either warnings or errors.

The Style Checker is also available for download as a set of XSL stylesheets. The downloadable version has the same functionality as the web-based version but it can be run locally. If you are unfamiliar with running XSL stylesheets against XML data, please use the web-based version.