1. Commodity Stabilization Service. The Pesticide Situation for 1957–58, U.S. Department of Agriculture, April 1958.
2. Elton, Charles S. The Ecology of Invasions by Animals and Plants. New York: Wiley, 1958.
3. Report on Environmental Health Problems. Hearings before the Subcommittee of the Committee on Appropriations. House of Representatives, 86th Congress, 2nd Session, 1960.
4. Shepard, Paul. “The Place of Nature in Man’s World.” Atlantic Naturalist, Vol. 13 (1958): 85–89.