Reptiles of the world: tortoises and turtles, crocodilians, lizards and snakes of the eastern and western hemispheres - Ditmars, Raymond Lee, 1876 -1942 (Sturgis and Walton, 1910)

The reptiles of western North America, an account of the species known to inhabit California and Oregon, Washington, Idaho, Utah, Nevada, Arizona, British Columbia, Sonora and Lower California - Van Denburgh, John, 1872 -1924 (California Academy of Sciences, 1922)

Reptilien und Amphibien - Werner, Franz, 1867 -1939 (G.J. Göschen'sche Verlagshandlung, 1908)

Rerum naturalium historia nempe quadrupedum, insectorum, piscium variorumque marinorum corporum fossilium, plantarum exoticarum ac praesertim testaceorum exsistium in Museo Kircheriano - Carattoni, Girolamo, 1749 -approximately 1809 (In typographia Zempelliano, aere venantii monaldini bibliopolae, 1773)

Researches upon the venom of the rattlesnake : with an investigation of the anatomy and physiology of the organs concerned - Mitchell, S. Weir (Silas Weir), 1829 -1914 (Smithsonian Institution, 1860)