↑Cope, E.D. (1892) A critical review of the characters and variations of the snakes of North America., Proc. US. Natl. Mus. 14: 589-694
↑ 3.03.1Cope, E.D. (1886) In: Ferrari-Perez: Catalogue of animals collected by the geographical and exploring commission of the Republic of Mexico. [Part III. Reptiles and Amphibians, pp. 182-199]., Proc. US Natl. Mus. 9: 125-199
↑ 4.04.1Bisby F.A., Roskov Y.R., Orrell T.M., Nicolson D., Paglinawan L.E., Bailly N., Kirk P.M., Bourgoin T., Baillargeon G., Ouvrard D. (ed.) (2011). "Species 2000 & ITIS Catalogue of Life: 2011 Annual Checklist". Species 2000: Reading, UK. Ginkuhà 24 Septyembre 2012.CS1 maint: multiple names: authors list (link) CS1 maint: extra text: authors list (link)