Da Costa Prudente, A. L., Da Silva, M. A. A., Da Rocha, W. A., & Franco, F. L. (2008). Morphological variation in Xenoxybelis boulengeri (Procter, 1923) (Serpentes, Xenodontinae, Philodryadini). Zootaxa, 1743(1), 53–61. https://doi.org/10.11646/zootaxa.1743.1.5