GovInfo provides free public access to official publications from all three branches of the Federal Government, with comprehensive advanced search and browse options. Some things you can find in GovInfo include: Budget of the United States, Commerce Business Daily, Congressional Directory, Congressional Record, Economic Indicators, Economic Report of the President, Government Accountability Office Reports, U.S. Government Manual, and the Weekly Compilation of Presidential Documents. GovInfo replaced FDsys in 2018.
With the exception of some periodical titles, federal publications are arranged on the shelf by an alphanumeric system called the Superintendent of Documents Classification Scheme (SuDocs).
Letters stand for the publishing agency, for instance
A for Agriculture
C for Commerce
L for Labor
Pr for President
and so forth
The numbers on the top line of the call number file differently than the Dewey or LC collections. The number following the period is a whole number NOT A DECIMAL.
C 3.9 .nine files before
C 3.44 .forty-four, which files before
C 3.223 .two hundred-twenty-three