United States. Civil Aeronautics Board. Office of the Secretary. (1968). International and overseas air routes of United States carriers, including Hawaii and Alaska mainland routes: December 31, 1968.
Chicago Style (17th ed.) CitationUnited States. Civil Aeronautics Board. Office of the Secretary. International and Overseas Air Routes of United States Carriers, Including Hawaii and Alaska Mainland Routes: December 31, 1968. [Washington, 1968.
MLA (8th ed.) CitationUnited States. Civil Aeronautics Board. Office of the Secretary. International and Overseas Air Routes of United States Carriers, Including Hawaii and Alaska Mainland Routes: December 31, 1968. 1968.
Warning: These citations may not always be 100% accurate.