1. M. V. Lomonosov, Complete Works (Akad. Nauk SSSR, Moscow, 1950–1983), Vol. 6 [in Russian].
2. http://www.gks.ru/free_doc/new_site/perepis2010/perepis_itogi1612.htm.
3. N. M. Rimashevskaya, Man and Reforms: Secrets of Survival (ISEPN RAN, Moscow, 2003) [in Russian].
4. A. A. Shabunova, M. V. Morev, and N. A. Kondakova, Children’s Health: Fifteen Years of Monitoring (ISERT RAN, Vologda, 2012).
5. https://ria.ru/20170913/1504653450.html.