APA (7th ed.) Citation

Ash, S. H., & Schoning, J. G. (1930). Rock-dusting in coal mines of State of Washington. [publisher not identified].

Chicago Style (17th ed.) Citation

Ash, S. H., and John G. Schoning. Rock-dusting in Coal Mines of State of Washington. Washington, D.C.: [publisher not identified], 1930.

MLA (9th ed.) Citation

Ash, S. H., and John G. Schoning. Rock-dusting in Coal Mines of State of Washington. [publisher not identified], 1930.