APA (7th ed.) Citation

United States. Government Printing Office. (1931). Monotype keyboard and casting machine. GPO.

Chicago Style (17th ed.) Citation

United States. Government Printing Office. Monotype Keyboard and Casting Machine. [Washington]: GPO, 1931.

MLA (9th ed.) Citation

United States. Government Printing Office. Monotype Keyboard and Casting Machine. GPO, 1931.

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