https://lansinginstitute.org/2021/10/12/russian-intelligence-focus-in-bulgaria/
https://novayagazeta.ru/articles/2021/10/07/gazprom-idet-na-shantazh
https://www.radiosvoboda.org/a/viyna-ukrayiny-z-rosiyeyu-na-usikh-frontakh/31489090.html
https://www.kp.ru/daily/28335.5/4480309/