Smith, H.M., and E.D. Brodie Jr. (1982). Reptiles of North America: A Guide to Field Identification. New York: Golden Press. 240 pp. ISBN0-307-13666-3 (paperback). (Nerodia c. cyclopion, p. 154).
Wright, A.H., and A.A. Wright (1957). Handbook of Snakes of the United States and Canada. Ithaca and London: Comstock Publishing Associates a division of Cornell University Press. 1,105 pp. (in 2 volumes). (Natrix cylopion cyclopion, pp. 472-475, Figure 139 + Map 38 on p. 467).
Conant, R., and W. Bridges (1942). What Snake Is That? A Field Guide to the Snakes of the United States East of the Rocky Mountains. (with 108 drawings by Edmond Malnate). New York and London: D. Appleton-Century. Frontispiece map + viii + 163 pp. + Plates A-C, 1-32. (Natrix cyclopion cyclopion, pp. 90-91).
