United States. Army. Air Corps. (1921). The "1920" model Hart reversible propeller manual and parts list. U.S. GPO.
Chicago Style (17th ed.) CitationUnited States. Army. Air Corps. The "1920" Model Hart Reversible Propeller Manual and Parts List. Washington: U.S. GPO, 1921.
MLA (9th ed.) CitationUnited States. Army. Air Corps. The "1920" Model Hart Reversible Propeller Manual and Parts List. U.S. GPO, 1921.
Warning: These citations may not always be 100% accurate.