https://www.kommersant.ru/doc/5051249
https://tyzhden.ua/%D0%A1%D0%B2%D1%96%D1%82/253450
https://www.nytimes.com/2021/10/25/us/politics/russia-cybersurveillance-biden.html
http://www.kasparov.ru/material.php?id=617293B719EFC
https://jamestown.org/program/the-eu-russia-antagonism-stretches-from-ukraine-to-the-arctic/
https://www.rosbalt.ru/blogs/2021/10/14/1926232.html
https://lansinginstitute.org/2021/10/12/russian-intelligence-focus-in-bulgaria/