The Federal Register is the official daily publication for rules, proposed rules, and notices of Federal agencies and organizations, as well as executive orders and other presidential documents.
The Code of Federal Regulations (CFR) annual edition is the codification of the general and permanent rules published in the Federal Register by the departments and agencies of the Federal Government.
The following describes how information is contained in a CFR citation from govinfo Help:
Title: Is the numeric value to the left of "CFR".
Part: Is the numeric value to the right of "CFR" and preceding the period (".").
Section/Subpart: Is the numeric value to the right of the period (".").
A subpart is a letter of the alphabet (A-Z) that is used to retrieve an entire subpart of the CFR rather than many individual sections. For example: Subpart E.
Revision Year: The four digit year from the "Revised as of" text represents the year being cited. The revision year is not always available when the CFR is cited.
The following example illustrates information contained in a CFR citation.
21 CFR 310.502 Revised as of April 1, 1997