Kuleshov, Viacheslav Sergeyevich. “A Periodization of Monetary Circulation of Mid-8th - Early 11th Centuries in Eastern Europe and the Dynamics of Economic Relationships of the Oldest Russian Squads”. Administrative Consulting, no. 2, Mar. 2016, pp. 169-7, https://administrative-consulting.owebs.ru/article/view/13034.