APA (7th ed.) Citation

United States. National Park Service. (1991). Endangered species in the national parks. U.S. Department of the Interior, National Park Service.

Chicago Style (17th ed.) Citation

United States. National Park Service. Endangered Species in the National Parks. [Washington, D.C.]: U.S. Department of the Interior, National Park Service, 1991.

MLA (9th ed.) Citation

United States. National Park Service. Endangered Species in the National Parks. U.S. Department of the Interior, National Park Service, 1991.