Y. G. Volkov, F. A. Barkov, A. V. Vereshchagina, O. Y. Posuhova, A. V. Serikov, and V. V. Chernous, “Middle class in the Rostov Region: behavioural strategy and social resources of formation”, Humanities of the South of Russia, no. 1, pp. 45-59, Jan. 2015.