References
- Thomas L. The medusa and the snail. New York: Viking Press, 1979
- Osler W. Osler's textbook revisited. East Norwalk, CT: Appleton-Century-Crofts, 1967: 59
- Lincoln A. Address before Wisconsin State Agricultural Society, Milwaukee, September 30,1859. In: Beck EM, ed. Bartlett's familiar quotations. 14th ed. Boston: Little, Brown. 1968: 636