Authors	Year	Title
Nassichuk & Furnish	1970	Christioceras, an Artic Pennsylvanian ammonoid, discovered in West Texas. Journal of Paleontology, 44 (2): 399-401, fig.1-3.
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.
Plummer	1950	The Carboniferous rocks of the Llano region of Central Texas. Publications of the University Texas, 4329: 1-170, pl.1-21; Austin.