Cadle, J. E. (2011) “Hemipenial morphology in the North American snake genus Phyllorhynchus (Serpentes: Colubridae), with a review of and comparisons with natricid hemipenes”, Zootaxa. Auckland, New Zealand, 3092(1), pp. 1–25. doi: 10.11646/zootaxa.3092.1.1.