Krysko, K. L., and W. S. Judd. “Morphological Systematics of Kingsnakes, Lampropeltis getula Complex (Serpentes: Colubridae), in the Eastern United States”. Zootaxa, vol. 1193, no. 1, May 2006, pp. 1–39, doi:10.11646/zootaxa.1193.1.1.