APA (7th ed.) Citation

United States. Bureau of Mines. (1937). Curves for classification of coal. [s.n.].

Chicago Style (17th ed.) Citation

United States. Bureau of Mines. Curves for Classification of Coal. [Washington]: [s.n.], 1937.

MLA (9th ed.) Citation

United States. Bureau of Mines. Curves for Classification of Coal. [s.n.], 1937.

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