	Authors	Year	Title
	Boardman & Work	2004	Stratigraphic distribution of the ammonoids Shumardites and Vidrioceras and implications for the definition of the global Gzhelian Stage, Upper Pennsylvanian Series, Upper Pennsylvanian Series. Newsletter on Carboniferous Stratigraphy, 22: 23-27, 2 fig.
	Miller & Downs	1950a	Ammonoids of the Pennsylvanian Finis Shale of Texas. Journal of Paleontology, 24:185-218, 11 text-figs., pl.31-35.
	Zakharov	1978	Novye nakhodki goniatitov v otlozheniiakh karbona khr. Karachatyr (Yuzhnaia Fergana). Uzbekskii geol. Zhurnal, Akad. Nauk Uzbekskoi SSR, 1978 (3): 50-54, 2 text-fig.