050 Subfield $b - Item number:

Subfield $b contains the item number portion of the call number. An item number is the Cutter, date, term, etc. that is added to a classification number to distinguish an item from any other item assigned the same classification number. Organizations that use the Cutter-Sanborn Three-Figure Author Table may conform to Library of Congress item number practice by applying Subject Cataloging Manual: Shelflisting conventions.

Examples:

050 00$aJX1974.7$b.M5

050 00$aZ763.L7$bY

050 10$aHF5726$b.B27 1980

050 00$aE506.5 6th$bG

050 00$aE514.6 10th$b.T76 1905

[The above two call numbers are call numbers for regimental histories.]