The Government Publishing Office provides a complete explanation of the Superintendent of Documents Classification System.
1. Periods, back slashes, and colons separate each section of a SuDoc Number. Documents are shelved alphabetically by the letters and then numerically, section by section.
C 1.1:
C 1.2:
C 1.24:
C 2.1:
2. All numbers are shelved as whole numbers, not decimals.
HE 20.40
HE 20.108:
HE 20.3016:
3. Single letters are shelved before multiple letters. Multiple letters are shelved alphabetically, regardless of the number of letters.
L 2.3:
LC 4.7:
N 11.5:
NAS 1.21:
NS 1.2: