https://www.dw.com/ru/pytki-v-sizo-i-kolonijah-v-rossii-kak-sistema-otstaivaet-svoih/a-60577106
https://www.bbc.com/russian/features-59778079
https://www.foreignaffairs.com/articles/russian-federation/2020-06-09/pinning-down-putin
http://www.ng.ru/politics/2018-05-03/100_politimigr.html