@article{articlea0852919,
title   = {Hemipenial morphology of the south american xenodontine snakes, with a proposal for a monophyletic xenodontinae and a reappraisal of colubroid hemipenes},
author = {Zaher, Hussam El Dine},
year = {1999},
journal   = {Bulletin of the American Museum of Natural History}
}