	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.
	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.