1. Benton, M.J., Sennikov, A.G., Newell, A.J.: Murchison’s first sighting of the Permian, at Vyazniki in 1841. Proc. Geol. Assoc. 121, 313–318 (2010)
2. Buzmakov, S.A., (ed.): Atlas osobo ohranjaemyh prirodnyh territorij Permskogo kraja [Atlas of Reserved Areas of the Perm Krai]. 512 p. (2017). (in Russian)
3. Buzmakov, S.A., Zajcev, A.A., Sannikov, P.: Actual review of the Perm Krai protected areas network. Voprosy stevedeniya [Problems of Steppe science]. 15, 55–58 (2019). (in Russian)
4. Chuvashov, B.I.: Istoriya izucheniya permskoj sistemy i etapy ee ustanovleniya v Rossii. In: Permskaya sistema: stratigrafiya paleontologiya, paleogeografiya, geodinamika i mineral'nye resursy: sb. materialov Mezhdunar. nauch. konf., posvyashchennoj 170-letiyu so dnya otkrytiya permskoj sistemy (5–9 sent. 2011., Perm) / Perm. gos. un-t. Perm, pp. 8–17 (2011). (in Russian)
5. Chuvashov, B.I., Chernykh, V.V.: Kungurian Stage of the General Stratigraphic Scale of the Permian System. In: Doklady RAN [RAS Proseedings], Vol. 375, 3. Pp. 370–374 (2000). (in Russian)