APA (7th ed.) Citation

Devries, R. P. (1912). Comparison of 5 methods used to measure hardness. U.S. Government Printing Office.

Chicago Style (17th ed.) Citation

Devries, Ralph P. Comparison of 5 Methods Used to Measure Hardness. [Washington?]: U.S. Government Printing Office, 1912.

MLA (9th ed.) Citation

Devries, Ralph P. Comparison of 5 Methods Used to Measure Hardness. U.S. Government Printing Office, 1912.