United States. National Advisory Committee for Aeronautics. (1939). Tandem air propellers. [s.n.].
Chicago Style (17th ed.) CitationUnited States. National Advisory Committee for Aeronautics. Tandem Air Propellers. [Washington]: [s.n.], 1939.
MLA (9th ed.) CitationUnited States. National Advisory Committee for Aeronautics. Tandem Air Propellers. [s.n.], 1939.
Warning: These citations may not always be 100% accurate.