	Authors	Year	Title
	Gordon	1965	Carboniferous Cephalopods of Arkansas. Professional Papers, U.S. Geological Survey, 460: 1-322, fig.1-96, pl.1-32; Washington. [imprint 1964].
	McCaleb	1968	Lower Pennsylvanian Ammonoids from the Bloyd Formation of Arkansas and Oklahoma. Special Paper of the geological Society of America, 96: 1-123, fig.1-27, pl.1-12; Boulder,Colorado.
	Miller & Moore	1938	Cephalopods from the Carboniferous Morrow Group of Northern Arkansas and Oklahoma. Journal of Paleontology, 12 (4): 341-374, fig.1-4, pl.43,44; Tulsa, Oklahoma.
	Quinn	1965	Reevaluation of Pygmaeoceras. Oklahoma Geology Notes, 25 (8): 228-236, fig.1-4; Norman.
	Saunders, Manger & Gordon	1977	Upper Mississippian and lower and middle Pennsylvanian ammonoid biostratigraphy of Northern Arkansas. Oklahoma Geolological Survey Guidebook 18: 117-137, fig.1-2, tab.1-2, pl.1-6.