	Authors	Year	Title
	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.
	Spinosa, Furnish & Glenister	1975	The Xenodiscidae, Permian ceratitoid ammonoids. Journal of Paleontology, 49 (2): 239-283, fig.1-22, tab.1-5, pl.1-8.