APA (7th ed.) Citation

Gustafson, A. F., Ries, H., Guise, C. H., & Hamilton, W. J. (1939). Conservation in the United States. Comstock Pub. Co..

Chicago Style (17th ed.) Citation

Gustafson, A. F., Heinrich Ries, Cedric H. Guise, and William John Hamilton. Conservation in the United States. Ithaca, N.Y.: Comstock Pub. Co., 1939.

MLA (9th ed.) Citation

Gustafson, A. F., et al. Conservation in the United States. Comstock Pub. Co., 1939.