The call numbers file alphabetically by letter and then in numerical order by the first group of numbers, then the next group, etc. All numbers are whole numbers. Unlike the Library of Congress call number system used in most of the rest of the library, there are no decimals.
The following are just a few of the agencies and departments:
Census Bureau (Commerce Department)
General Accounting Office
General Services Administration
Health and Human Services
Library of Congress
National Aeronautics and Space Administration
Internal Revenue Service (Treasury Department)
Department of Veteran Affairs
Reading SuDoc Numbers
First the letter or letters at the beginning
Note: "Nothing comes before something."
A 1.1:985 AC 1.1/2:975
Then numerically by the number, stopping at the period.
C 2.2:207 C 21.12/2:966
Then numerically by the whole number down to the next slash, period, or colon.
C 55.13:826 C 55.13/2:26
If at any time after the first period you must choose between a number and a letter, letters go before numbers.
Y 4.EC 7/a:92 Y 4.EC 7/2:86
Continue looking by the whole number or letter up to the next punctuation mark until the end of the call number.
Y 4.F 49:92-47 Y 4.F 49:857
The first thing to note is that SuDoc numbers always have a colon. There are two parts to a SuDoc number, the part before the colon, and the part after the colon. Also, all numbers are whole numbers, i.e., there are no decimals in a SuDoc number.
The SuDoc classification system in designed to group together publications by the same government author. Within an agency or department, publications are grouped according to the subordinate organization. The purpose of the system is to uniquely identify, logically relate, and physically arrange each publication so that all publications of a single agency or department may be found together.