United States. Postmaster General. (1932). Convention of Postal Union of the Americas and Spain and agreement concerning parcel post, effective with Ecuador, Paraguay, and Salvador. U.S. GPO.
Chicago Style (17th ed.) CitationUnited States. Postmaster General. Convention of Postal Union of the Americas and Spain and Agreement Concerning Parcel Post, Effective with Ecuador, Paraguay, and Salvador. Washington: U.S. GPO, 1932.
MLA (9th ed.) CitationUnited States. Postmaster General. Convention of Postal Union of the Americas and Spain and Agreement Concerning Parcel Post, Effective with Ecuador, Paraguay, and Salvador. U.S. GPO, 1932.
Warning: These citations may not always be 100% accurate.