	Authors	Year	Title
	Bogoslovskaya, Leonova & Shkolin	1995	The Carboniferous-Permian boundary and ammonoids from the Aidaralesh section, southern Urals. Journal of Paleontology 69: 288-301, 12 figs., Lawrence, KS.
	Glenister, Baker & Furnish	1990	Additional Early Permian ammonoid cephalopods from Western Australia. [Glenister,B.F., Baker,C., Furnish,W.M. & Thomas,G.A.] Journal of Paleontology, 64 (3): 392-399, fig.1-4, 1tab.; Tulsa, Okla.
	Ruzhencev	1952	Biostratigrafiya Sakmarskogo Yarusa v Aktyubinskoy Oblasti Kazakhskoy SSR. Trudy Paleontologicheskogo Instituta Akademiya Nauk SSSR, 42: 1-87, fig.1-28, pl.1-6; Moskva.