- Editorial, “The Welder of the Parks,” Saturday Evening Post, December 30, 1922, pp. 26–28.
- Harrison, Frank E., Assistant to the Director for Legislation and Regulations, National Park Service, interview, Washington, D. C., August 29, 1968.
- Ise, John, Our National Park Policy: A Critical History, New York, 1967, p. 323.
- Letter from Director of the National Park Service to Passenger Traffic Manager, Union Pacific System, February 13, 1932, in Box 173, National Park Records, National Archives, Washington, D. C.
- Letter from Passenger Traffic Manager, Union Pacific System, to Director of the National Park Service, February 5, 1932, in Box 173, National Park Records, National Archives, Washington, D. C.
- Letter from Secretary of the Interior to President of the National Parks Association, May 1, 1940, in Box 655, National Park Service Records, National Archives, Washington, D. C.
- Proceedings of the National Parks Conference, Washington, D.C., January 4-6, 1917, National Park Service, Washington, D.C., 1917, p. 45.
- Shankland, Robert, Steve Mather of the National Parks, New York, 1951, pp. v, vi, 263.
- Tilden, Freeman, The National Parks: What They Mean to You and Me, New York, 1955, p. 30.
- Ward, Henry B., “Origin and Objectives of the National Parks Association,” National Park Bulletin, July 1940, p. 5.
Environmental Education
Volume 2, 1971 - Issue 4