Mendelson III, Joseph R. (1998): Geographic Variation in Bufo valliceps (Anura: Bufonidae), a Widespread Toad in the United States and Middle America. - Scientific Papers Nat. Hist. Mus. Kansas, No. 8: 1,12.

Abstract, Introduction, Materials and Methods (Geographic Variation in Size, Qualitative Comparisons), Discussion (Body Size and Aridity, Crest Height and Elevation, Taxonomic Issues), Literature cited, Appendix.
 

Mendelson III, Joseph, R., Paul C. Ustach & Adrian Nieto Montes de Oca (1999): Description of the tadpole of Bufo tutelarius, natural history notes on the Bufo valliceps group and a key to the tadpoles of the group. - J. Herpetol., 33 (2): 324-328.
 

Myers, George S. (1930): The Status of the Southern California Toad, Bufo californicus (Camp). - Proc. Biol. Soc. Washington, Vol. 43: 73-78.
 

Myers, George S. & Antenor Leitao de Carvalho (1945): Notes on some new or little-known Brazilian Amphibians, with an Examination of the History of the Plata Salamander, Ensatina platensis. - Bol. do Mueso Nacional, Rio de Janeiro, No. 35: 2-24 + 15 SW-Tafeln.

Oedipus altamazonicus, Hemipipa carvalhoi, Bufo dapsilis, Hemiphractus scutatus, Cerathyla bubalus,
 

Patterson, Robert (1971): The role of urination in egg predator defense in the Desert Tortoise (Gopherus agassizi). - Herpetologica, 27 (2): 197-199.

In the desert tortoise Gopherus agassizi, the egg nest is urinated upon by the female as an aid to nesting digging, repulsion of egg predators, camouflage of the egg nest, and as a compaction agent that makes nest excavation difficult. Experimental tests were run using zoo animals, and soil penetration and compaction tests were supportive of the above conclusions. No bacteriostatic agent was found in tortoise urine.
 

Rauschenberger, R. H., S. E. Trauth & J. L. Farris (2004): Incubation of alligator snapping turtle (Macrochelys temminckii) eggs in natural and agricultural soils. - Applied Herpetology, Leiden, 1: 299-309.

Key words: Agriculture, alligator snapping turtle, egg, environmental contaminants, development, incubation, Macrochelys temminckii, reptile, soil, turtle.
 

Ruibal, Rodolfo (1959): Bufo gundlachi, a new species of Cuban toad. - Brevoria, Cambridge, No. 105: 1-14.
 

Schneider, Bert (1974): Beitrag zur Herpetofauna Tunesiens, I. Bufo bufo spinosus. - Salamandra, Frankfurt/M., 10 (2): 55-60.