List of Classes -- MS Excel formatGPO -- The List of Classes is a list of agency materials that libraries are able to select for their collections, and these selections constitute the library’s item selection profile. Current List of Classes files are automatically updated on the 1st and 15th of the month and contain the following fields: SuDoc Number, Issuing Agency, Title, Geography (if a title is state-oriented), Frequency (if known), and Item Number.