APA (7th ed.) Citation

United States. Government Printing Office. (1931). Copy preparing. GPO.

Chicago Style (17th ed.) Citation

United States. Government Printing Office. Copy Preparing. [Washington]: GPO, 1931.

MLA (9th ed.) Citation

United States. Government Printing Office. Copy Preparing. GPO, 1931.

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