1. Douglass C. North, Terry L. Anderson, and Peter J. Hill, Growth and Welfare in the American Past: A New Economic History (Englewood Cliffs, NJ: Prentice-Hall, 1983), 111–21.
2. Theodore Roosevelt, in Proceedings of the American Forest Congress (Washington, DC: American Forestry Association, 1905), 9.
3. Gifford Pinchot, The Fight for Conservation (New York: Doubleday and Page, 1910), 123–24.
4. Robert F. Fries, Empire in Pine:The Story of Lumber in Wisconsin (Madison: State Historical Society of Wisconsin, 1951), 8-23, 250-51
5. Ronald N. Johnson and Gary D. Libecap, Explorations in Economic History 17 (1980): 376-77;Agnes M. Larson, History of the White Pine Industry in Minnesota (Minneapolis: University of Minnesota Press, 1949), 11, 29-28, 220-21, 404