1958b. A preliminary analysis of the herpetofauna of Colima, Mexico. Occas. Papers Mus. Zool. Univ. Michigan, No. 589:1-22.
1958c. A review of the frogs of the genus Syrrhophus in western Mexico. Occas. Papers Mus. Zool. Univ. Michigan, No. 594:1-15, pls. 1-3.
Duellman, W. E., and Schwartz, A.
1958. Amphibians and reptiles of southern Florida. Bull. Florida State Mus., vol. 3 (5):181-324.
Dunn, E. R.
1942. The American caecilians. Bull. Mus. Comp. Zool., vol. 91 (6):439-540.
Durham, J. W., Arellano, A. R. V., and Peck, Jr., J. H.
1952. No Cenozoic Tehuantepec seaways. Bull. Geol. Soc. Amer., vol. 63:1245.
Firschein, I. L.
1950. A new toad from Mexico with a redefinition of the cristatus group. Copeia, 1950 (2):81-87, pl. 1.