APA (7th ed.) Citation

Helms, D., Effland, A. B. W., & Durana, P. J. (2002). Profiles in the history of the U.S. Soil Survey. Iowa State University Press.

Chicago Style (17th ed.) Citation

Helms, Douglas, Anne B. W. Effland, and Patricia J. Durana. Profiles in the History of the U.S. Soil Survey. Ames, Iowa: Iowa State University Press, 2002.

MLA (9th ed.) Citation

Helms, Douglas, et al. Profiles in the History of the U.S. Soil Survey. Iowa State University Press, 2002.