1954. Additions to the known herpetological fauna of Costa Rica with comments on other species. No. I. Univ. Kansas Sci. Bull., 36:597-639. June 1.
Taylor, E. H. and Smith, H. M.
1945. Summary of the collections of amphibians made in México under the Walter Rathbone Bacon Traveling Scholarship. Proc. U. S. Natl. Mus., 95:521-613, pls. 18-32. June 30.
Tihen, J. A.
1962. Osteological observations on New World Bufo. Amer. Midl. Nat., 67:157-183. January.
1965. Evolutionary trends in frogs. Amer. Zoologist, 5:309-318.
Vinson, G. L. and Brineman, J. H.
1963. Nuclear Central America, hub of Antillean Transverse Belt. Amer. Assoc. Petrol. Geol., Mem. 2:101-112.
Whitmore, F. C., Jr. and Stewart, R. H.
1965. Miocene mammals and Central American seaways. Science, 148:180-185. April 9.