Government documents use the Superintendent of Documents (SuDocs) classification system. SuDocs call numbers are issued by the Superintendent of Documents of the U.S. Government Printing Office to all official government publications. In this system materials are arranged by issuing agency, not by subject. The following is a brief outline of the SuDocs system.
The Federal Depository Library Program maintains a Current Lettering for SuDoc Class Stems.
Reading SuDocs Call Numbers
Government agencies publish material on a wide variety of subjects. Materials using this classification system are grouped together according to the agency that produced them, rather than by subject. This means that items concerning unrelated subjects may be located on the shelf next to each other, as long as they were produced by the same agency.
SuDocs call numbers consist of two parts: Agency number : book number
The agency number identifies the agency that created/generated the document and begin with letters of the alphabet. One or more numbers following the letter(s) represents a division of the primary agency.
C - Dept of Commerce C3 - Census Bureau I - Interior Dept I19 - U.S. Geological Survey IC - Interstate Commerce Commission
Complete SuDocs call number: C 3.134/2 : C 83/2/995
Issuing Department C Commerce Department Subagency 3 Bureau of the Census Series 134/2: Statistical Abstract Suppl. Title and date C 83/2/995 County and City Data Book, 1995
To locate a SuDocs call number on the shelf:
Numbers appearing before the ( . ) are read as whole numbers. Numbers appearing after the ( . ) are also read as whole numbers. Example:
A 88.62:P 32/5 A 88. 62 P 32/5 88 is read as a whole number 62 is read as a whole number
When a string of numbers is followed by words or abbreviations, the words should be read in alphabetical order.
Example: Y10.2:B 85/2/978-82/SUPP then Y10.2:B 85/2/978-82/UPDATE
SuDocs call numbers are divided into sections by periods ( . ) or colons ( : ) and sections can be divided by slashes ( / )or hyphens ( - ).
Example: Y 4.W64:W 325 then Y 4.W64/2:ST2 (W64: before W64/2:)
Letters that may follow punctuation are read alphabetically.
Example: SI 1.1/A:AE 82.5 then SI 1.1/A:B 615 (AE before B)