title: Regulations, proposals, guidelines, advisory opinions, and letters of advice: what legal significance?
authors.affiliation: Food and Drug Administration, Rockville, Maryland.
authors.forename: L R
authors.initials: LR
authors.lastname: Horton
mesh_terms: D003142:Communication; D014481:United States; D014486:United States Food and Drug Administration / Q000331:legislation & jurisprudence* / Q000458:organization & administration