Wright AH, Wright AA (1957). Handbook of Snakes of the United States and Canada. Ithaca and London: Comstock Publishing Associates (7th printing, 1985). 1,105 pp. (in 2 volumes). ISBN0-8014-0463-0.
Campbell JA, Lamar WW (2004). The Venomous Reptiles of the Western Hemisphere. Ithaca and London: Comstock Publishing Associates. 870 pp. 1,500 plates. ISBN0-8014-4141-2.
Parker HW, Grandison AGC (1977). Snakes — a natural history. Second Edition. London and Ithaca: British Museum (Natural History) and Cornell University Press. 108 pp. 16 plates. LCCCN 76-54625. ISBN0-8014-1095-9 (cloth), ISBN0-8014-9164-9 (paper).