	Authors	Year	Title
	Ruzhencev	1951	Nizhnepermskie ammonity yuzhnogo Urala. 1.Ammonity Sakmarskogo Yarusa. Trudy Paleontologicheskogo Instituta Akademiya Nauk SSSR, 33: 1-186, fig.1-62, phot.1-8, pl.1-15; Moskva.
	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.