'...&COMPOSITION_BASED_STATISTICS=1&...'
uses the composition based statistics described in [5].
.
Note: For 'PROGRAM=blastp' only. Use
'TWEAK_PARAMETERS=on' in wwwblast is equivalent
to '1'. Commandline blastpgp equivalent is '-t'.
Commandline blastp equivalent is '-C'. For details, see [5]
and [7].