APA (7th ed.) Citation

United States. Forest Service. (1985). Changing canyon trail. The Service.

Chicago Style (17th ed.) Citation

United States. Forest Service. Changing Canyon Trail. [Washington, D.C.?]: The Service, 1985.

MLA (8th ed.) Citation

United States. Forest Service. Changing Canyon Trail. The Service, 1985.

Warning: These citations may not always be 100% accurate.