APA (7th ed.) Citation

United States. Bureau of Mines. (1939). Experiments on strength of small pillars of coal in Pittsburgh bed. [s.n.].

Chicago Style (17th ed.) Citation

United States. Bureau of Mines. Experiments on Strength of Small Pillars of Coal in Pittsburgh Bed. [Washington]: [s.n.], 1939.

MLA (9th ed.) Citation

United States. Bureau of Mines. Experiments on Strength of Small Pillars of Coal in Pittsburgh Bed. [s.n.], 1939.