United States. National Park Service. (1923). Manual for motorists, Yellowstone National Park; season of 1923, June 20-Sept. 20. U.S. GPO.
Chicago Style (17th ed.) CitationUnited States. National Park Service. Manual for Motorists, Yellowstone National Park; Season of 1923, June 20-Sept. 20. Washington: U.S. GPO, 1923.
MLA (9th ed.) CitationUnited States. National Park Service. Manual for Motorists, Yellowstone National Park; Season of 1923, June 20-Sept. 20. U.S. GPO, 1923.
Warning: These citations may not always be 100% accurate.