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Guide to Interpreting SuDoc Classification Numbers

Tips for locating US Government Publications shelved using the Superintendent of Documents Classification System

Federal Depository Library Program

The Federal Depository Library Program (FDLP) was established by Congress to ensure that the American public has access to government information. As a selective federal depository library, Ottenheimer Library collects approximately 37 percent of the online and print publications 

Federal depository publications are shelved using the Superintendent of Documents Classification 

Ottenheimer Library publications are generally located  accordingly:

  • Paper volumes can be located in the stacks on the third floor.
  • Microfiche, CD-ROMs, DVDs and video cassettes are located on the third floor. 
  • Online materials can be accessed by searching Government Publication Office website and various online repositories, including the Ottenheimer library search 

Standard Information for all SuDoc Numbers

In the Superintendent of Documents (SuDocs) classification system, the call number is divided into two parts: the class number, or stem, and the individual book number.


A colon separates the class number from the book number. If the colon is followed by a letter, the publication is a monograph. If the colon is followed by a number, it is a serial.



              Civil War Manuscripts   LC 4.2: C 49

              LC          Library of Congress

 4             Manuscript Division                 

   .2          type of publication (General Publications)

   : C 49     individual book number



   Monthly Labor Review   L 2.6: 26/9

    L              Department of Labor

    2              Labor Statistics Bureau

    .6             type of publication (journal)

    :26           volume 26

   / 9             issue 9