Federal agencies (FCC, FDA, SEC, etc.) are responsible for creating, enforcing, and interpreting rules and regulations.   The regulations themselves are relatively easy to locate, thanks to HeinOnline's Code of Federal Regulations and Federal Register databases.   Federal agency documents and decisions (which interpret and apply regulations) can be more difficult to track down.   If HeinOnline's database on "Federal Agency Documents and Decisions" doesn't contain what you need, it may be necessary to go directly to the federal agencies web site to located the required information.    You can also check the U.S. government web site, fdsys.gov.