Artyushkova Olga V., Dub Semyon A., Evdokimova Irina O., Mel’nichuk Oleg Yu., Tel’nova Olga P. «Middle and Upper Devonian boundary units in «Pokrovskoe» section (Middle Urals Eastern Slope). History of study and new research results» // Geosphere Research 2025. №3 C.19-40