APA (7th ed.) Citation

Gardner, E. D. (1930). Undercut block-caving method of mining in western copper mines. [publisher not identified].

Chicago Style (17th ed.) Citation

Gardner, E. D. Undercut Block-caving Method of Mining in Western Copper Mines. Washington, D.C.: [publisher not identified], 1930.

MLA (9th ed.) Citation

Gardner, E. D. Undercut Block-caving Method of Mining in Western Copper Mines. [publisher not identified], 1930.