Reference(s):

Carroll, R. L., 1988: Vertebrate paleontology and evolution.
–W. H. Freeman and company, New York, 1988, 698

Carroll, R. L., 1988: Appendix. 594-648.
in Carroll, R. L. 1988: Vertebrate paleontology and evolution.
–W. H. Freeman and company, New York, 1988, 698.

Lahti, S., Malmström, K. K., Koli, L., Leikola, A., Syrjämäki, J. & Lahti, J., 1980: Zoo, Suuri Eläinkirja 5: Kalat, sammakkoeläimet, matelijat. --Werner Söderström Osakeyhtiö, Porvoo-Helsinki-Juva, 1980. Original publication [in French]: Beauté Du Monde Animal: IX Reptiles/Amphibiens & X Poissons Rizzoli Editore, Milano 1968. Uetz, P., Etzold, T. & Chenna, R., 1995-2000: Family Colubridae (Colubrids). –iNet: The TIGR Reptile Database [former EMBL Reptile Database]: http://www.embl-heidelberg.de/~uetz/families/Colubridae.html