APA (7th ed.) Citation

Swanson, E. W. (1969). Travel and the national parks: An economic study. [National Park Service].

Chicago Style (17th ed.) Citation

Swanson, Ernst W. Travel and the National Parks: An Economic Study. [Washington, D.C.]: [National Park Service], 1969.

MLA (9th ed.) Citation

Swanson, Ernst W. Travel and the National Parks: An Economic Study. [National Park Service], 1969.