TY JOUR TI LEGAL CUSTOMS OF ANCIENT RUSSIA AS SOURCE OF LAW KW Custom KW common law KW types of common law KW signs of common law KW procedural rules KW transformation of customs in common law JO Vestnik of the East Siberian institute of the Ministry of internal affairs of the Russian Federation AU Chernih, V.V. AU Tsykunov, G.A. PY 2017 IS PB East Siberian institute of the Ministry of Internal Affairs of the Russian Federation