	Authors	Year	Title
	Davis	1972	Mature modifications and dimorphism in selected Late Paleozoic ammonoids. Bulletins of American Paleontology, 62 (272): 27-130, pls.3-21, Ithaca, NY.
	Girty	1908	The Guadalupian Fauna. Professional Papers, U.S. Geological Survey, 58: 1-651, pl.1-31; Washington.
	Lambert, Lehrmann & Harris	2000	Correlation of the Road Canyon and Cutoff Formations, West Texas, and Its Relevance to Establishing an International Middle Permian (Guadalupian) Series In: Wardlaw,B.R., Grant,R.E. & Rohr,D.M.: The Guadalupian Symposium, Smithsonian Contributions to the Earth Sciences, 153-183, 4 pl., 11 fig., Washington.
	Miller & Furnish	1940c	Permian ammonoids of the Guadalupe Mountain Region and adjacent areas. Special Papers of the Geological Society of America, 26: 1-242, fig.1-59, pl.1-44; Baltimore.
	Plummer & Scott	1937	Upper Paleozoic ammonites in Texas. The geology of Texas, vol.3 pt.1, Bull. Texas. Univ., 3701: 1-516, fig.1-88, pl.1-41; Austin, Texas.