APA (7th ed.) Citation

Pirkle, E. C., & Yoho, W. H. (1977). Natural regions of the United States (2nd ed.). Kendall/Hunt Pub. Co..

Chicago Style (17th ed.) Citation

Pirkle, E. C., and W. H. Yoho. Natural Regions of the United States. 2nd ed. Dubuque, Iowa: Kendall/Hunt Pub. Co., 1977.

MLA (9th ed.) Citation

Pirkle, E. C., and W. H. Yoho. Natural Regions of the United States. 2nd ed. Kendall/Hunt Pub. Co., 1977.