Giri, Rohit, et al. “An Unusually Dark Common Trinket Snake, Coelognathus Helena (Daudin 1803) (Colubridae), from Nepal ”. Reptiles & Amphibians, vol. 27, no. 2, July 2020, pp. 247-8, https://doi.org/10.17161/randa.v27i2.14195.