APA (7th ed.) Citation

United States. Army. Air Corps. (1920). Observation, selection, and assignment. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Army. Air Corps. Observation, Selection, and Assignment. Washington: U.S. GPO, 1920.

MLA (9th ed.) Citation

United States. Army. Air Corps. Observation, Selection, and Assignment. U.S. GPO, 1920.

Warning: These citations may not always be 100% accurate.