Agencies continually interpret the statutes they administer. Their interpretations are expressed in a great variety of forms-in legislative regulations, adjudicatory opinions, manuals, court briefs, interpretive rules, policy statements, staff instructions, opinion letters, audits, correspondence, informal advice, guidelines, press releases, testimony before Congress, internal memoranda, speeches, explanatory statements in the Federal Register, and others.
Robert A. Anthony,
Which Agency Interpretations Should Bind Citizens and the Courts?,
Yale J. on Reg.
Available at: http://digitalcommons.law.yale.edu/yjreg/vol7/iss1/2