Form:

Code b (008/17) indicates that the 1XX heading is an authorized form subdivision.

Examples:

008/17   b

008/09   d  [subdivision record]

180  ##  $xcongresses

008/17   b

008/09   g  [reference and subdivision record]

150  ##  $aDictionaries

260  ##  $isubdivision$aDictionaries$iunder specific subject terms