APA (7th ed.) Citation

United States. National Park Service. (1981). Petrified Forest National Park, Arizona (Scale [ca. 1:120,000].). The Service.

Chicago Style (17th ed.) Citation

United States. National Park Service. Petrified Forest National Park, Arizona. Scale [ca. 1:120,000]. [Washington, D.C.?]: The Service, 1981.

MLA (9th ed.) Citation

United States. National Park Service. Petrified Forest National Park, Arizona. Scale [ca. 1:120,000]. The Service, 1981.