Federal Regulation research is divided into two separate areas: (1) administrative law, which deals with the validity and creation of agency created law; and (2) the research of the agency law itself. This series of research guides deals with the latter.
Comments will often be received in response to the public notice published in the Federal Register. It is not uncommon for the comment period to be extended. Comments may be requested at the same time as other agency actions such as an advanced notice of proposed rulemaking, a direct final rule, and an interim rule.
What to look for:
Federal Register document with action final rule. (Prelim has section summarizing comments and the agency's response to them.)