Vikhlyaev , V. I., A. Y. Zeleneev, and Y. A. Zeleneev. “Trans-Kama and Penza Defensive Lines of the Russian State I N the Second Half of the XVII Century”. Arkheologiia Evraziiskikh Stepei (Archaeology of the Eurasian Steppes), no. 6, Dec. 2023, pp. 103-10, doi:10.24852/2587-6112.2023.6.103.110.