TY JOUR TI Assemblages of vertebrates and zones from the Upper Givetian and Lower Frasnian of the East European Platform and Urals KW ichthyofauna KW zones KW Givetian — Frasnian KW East European Platform KW Urals JO Vestnik of geosciences AU Ivanov, A.O. PY 2023 IS 0 PB FSBI FIC "Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences"