APA (7th ed.) Citation

Gardner, E. D., & Johnson, C. H. (1934). Placer mining in the western United States. U.S. Bureau of Mines.

Chicago Style (17th ed.) Citation

Gardner, E. D., and Charles H. Johnson. Placer Mining in the Western United States. [Tucson?, Ariz.]: U.S. Bureau of Mines, 1934.

MLA (8th ed.) Citation

Gardner, E. D., and Charles H. Johnson. Placer Mining in the Western United States. U.S. Bureau of Mines, 1934.

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