APA (7th ed.) Citation

United States. Army. Corps of Engineers. (1921). Manual of topography: Chapter A-2. Conventional signs. [publisher not identified].

Chicago Style (17th ed.) Citation

United States. Army. Corps of Engineers. Manual of Topography: Chapter A-2. Conventional Signs. Washington: [publisher not identified], 1921.

MLA (9th ed.) Citation

United States. Army. Corps of Engineers. Manual of Topography: Chapter A-2. Conventional Signs. [publisher not identified], 1921.

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