Vybornov, A., et al. “The Problems With Neolithization Chronology in The East European Steppe and Forest-Steppe (From the Volga River to the Don River)”. International Journal of Engineering & Technology, vol. 7, no. 4.38, Dec. 2018, pp. 1254-8, https://doi.org/10.14419/ijet.v7i4.38.27799.