APA (7th ed.) Citation

Cash, F. E., & Humphrey, H. B. (1930). Explosions in Alabama coal mines. [publisher not identified].

Chicago Style (17th ed.) Citation

Cash, Frank E., and H. B. Humphrey. Explosions in Alabama Coal Mines. Washington, D.C.: [publisher not identified], 1930.

MLA (9th ed.) Citation

Cash, Frank E., and H. B. Humphrey. Explosions in Alabama Coal Mines. [publisher not identified], 1930.