Federal agency decisions arise from proceedings by an agency to enforce its rules. Adjudicatory heariings are held primarily to impose sanctions on an individual or organization and are conducted by an administrative law judge. Agencies also frequently provide advice letters, guidance and other rulings, which are published with its decisions, or in separate compilations, e.g. S.E.C. no-action letters.
Looseleaf Publications: There are a variety of looseleaf services, e.g., Standard Federal Tax Reporter, that publish administrative decisions, along with the text of regulations and expert commentary. The Bluebook provides an extensive listing of these looseleaf publications under Table 15: "Services". Once you have identified a relevant title, you should consult the library catalog to determine availability and location.
Agency Websites: Many agencies offer online access to their administrative decisions on their websites.
Law Databases: Some law databases, such as Lexis, Westlaw, and HeinOnline, include federal agency decisions.