↑Craven, S.R. & Knudsen, G.J. (1996) Snakes of Wisconsin., University of Wisconsin.
↑Cope, E.D. (1893) On a collection of batrachia and reptilia from southwest Missouri., Proc. Acad. Nat. Sci. Philadelphia 1893: 383-385
↑ 4.04.1Kennicott (1859) Notes on coluber calligaster of Say, and a description of a new species of Serpents in the collection of the north Western University of Evanston,Ill., Proc. Acad.Nat. Sci. Philadelphia 11: 98-100
↑ 5.05.1Bisby 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)