(Crotaphytus collaris), with a Description of a New Subspecies". Transactions of the Kansas Academy of Science 54 (4): 548–559. (Crotaphytus collaris auriceps, new subspecies). Ingram W, Tanner WW (1971). "A taxonomic study of Crotaphytus collaris between the Rio Grande and Colorado Rivers". Brigham Young University Science Bulletin 13 (2): 1–29. (Crotaphytus collaris fuscus, new subspecies). Powell R, Conant R, Collins JT (2016). Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, Fourth Edition. Boston and New York: Houghton Mifflin Harcourt. 494 pp., 47 plates, 207 figures. . (Crotaphytus collaris, pp. 276–277, Figure 132 + Plate 24). Say T (1823). In: James E (1823). Account of an Expedition from Pittsburgh to the Rocky Mountains, Performed in the Years 1819 and '20, by order of the Hon. J.C. Calhoun, Sec'y of War: Under the Command of Major Stephen H. Long. From the Notes of Major Long, Mr. T. Say, and other Gentlemen of the Exploring Party. Vol. II. Philadelphia: H.C. Carey and I. Lea. 442 pp. (Agama collaris, new species, p. 252). Smith HM, Brodie ED Jr (1982). Reptiles of North America: A Guide to Field Identification. New York: Golden Press. 240 pp. (paperback), (hardcover). (Crotaphytus collaris, pp. 106–107). Stejneger L (1890). "Annotated List of Reptiles and Batrachians Collected by Dr. C. Hart Merriam and Vernon Bailey on the San Francisco Mountain Plateau and Desert of the Little Colorado, Arizona, with Descriptions of New Species". North American Fauna (3): 103–118. (Crotaphytus baileyi, new species, pp. 103–105 + Plate XII, figure 1).). Crotaphytus Reptiles of the United States Reptiles of Mexico Reptiles described in 1823 Taxa named by Thomas Say