https://jamestown.org/program/the-eu-russia-antagonism-stretches-from-ukraine-to-the-arctic/
https://lansinginstitute.org/2021/10/12/russian-intelligence-focus-in-bulgaria/
https://www.ng.ru/armies/2021-10-07/2_8272_fleet.html
https://www.rbc.ru/newspaper/2021/10/07/615da0ca9a7947e2cd6453c1
https://jamestown.org/program/the-realities-of-russian-military-shipbuilding-part-one/
https://www.rbc.ru/newspaper/2021/10/04/61571a279a79478e0bc0b011
https://www.kp.ru/daily/28335.5/4480309/
https://jamestown.org/program/russias-military-boosts-electromagnetic-spectrum-capability/