Style de citation APA (7e éd.)

United States. National Park Service, Yard, R. S., & Story, I. F. (1931). The national parks portfolio (6th ed.). U.S. Govt. Print. Off..

Style de citation Chicago (17e éd.)

United States. National Park Service, Robert Sterling Yard, et Isabelle F. Story. The National Parks Portfolio. 6th ed. Washington: U.S. Govt. Print. Off., 1931.

Style de citation MLA (8e éd.)

United States. National Park Service, et al. The National Parks Portfolio. 6th ed. U.S. Govt. Print. Off., 1931.

Attention : ces citations peuvent ne pas être correctes à 100%.