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E. D.  Cope, ?Contributions to Neotropical saurology.?, Proceedings of the Academy of Natural Sciences of Philadelphia, vol. 14, pp. 176?188, 1862.

E. D.  Cope, ?On the batrachia and reptilia of Costa Rica.?, Journal of the Academy of Natural Sciences of Philadelphia, new series, vol. 8, pp. 93?154, 1875.

E. D.  Cope, ?An Examination of the Reptilia and Batrachia Obtained by the Orton Expedition to Equador and the Upper Amazon , with Notes on Other Species.?, Proceedings of the Academy of Natural Sciences of Philadelphia, vol. 20, pp. 96?140, 2012.