Jansen, M., L. G. Álvarez, and G. Köhler. “Description of a New Species of Xenopholis (Serpentes: Colubridae) from the Cerrado of Bolivia, With Comments on Xenopholis Scalaris In Bolivia”. Zootaxa, vol. 2222, no. 1, Sept. 2009, pp. 31–45, doi:10.11646/zootaxa.2222.1.3.