@article{Orlov2018socio-demographic,
author={Orlov, E.V. and Propletkina, D.G.},
title={Socio-demographic problems of cities with over one mil-lion people in Russia},
journal={Journal of sociological research},
publisher={INFRA-M Academic Publishing LLC.},
year={2018},
pages={16-21},
volume={3},
issue={2},
}