Johnson, C.
1959. Genetic incompatibility in the call races of Hyla versicolor Le Conte in Texas. Copeia, no. 4:327-335. December 30.
Lloyd, J. J.
1963. Tectonic history of the south Central-American Orogen. Amer. Assoc. Petrol. Geol., Mem. 2:88-100.
Maldonado-Koerdell, M.
1964. Geohistory and paleogeography of Middle America, in Wauchope, R. and West, R. C. (Eds.). Handbook of Middle American Indians, vol. 1, Univ. Texas Press, Austin, 570 pp.
Maslin, T. P.
1963. Notes on some anuran tadpoles from Yucatán, México. Herpetologica, 19:122-128. July 3.
Mittleman, M. B. and List, J. C.