Gubaidullin , Airat M. 2023. “Studies of Bolgar Fortified Settlements Defensive Structures by A.P. Smirnov”. Arkheologiia Evraziiskikh Stepei (Archaeology of the Eurasian Steppes), no. 6 (December):221-30. https://doi.org/10.24852/2587-6112.2023.6.221.230.