Fedoseev, R. V., O. I. Mariskin, and E. D. Bogatyrev. “The Crisis of Noble Land Ownership in the Second Half of XIX - Early XX Century (based on Materials from the Middle Volga Region)”. Amazonia Investiga, vol. 8, no. 20, June 2019, pp. 104-1, https://mail.amazoniainvestiga.info/index.php/amazonia/article/view/69.