KOPYTOV, S.V.; DEMAKOV, D.A. NATURAL SURROUNDINGS OF MEDIEVAL SOCIETIES IN THE UPPER KAMA VALLEY. Perm Federal Research Centre Journal, [S. l.], n. 3, p. 6–14, 2017. Disponível em: https://journal.permsc.ru/index.php/pscj/article/view/PSCJ2016n3p2. Acesso em: 13 may. 2026.