https://www.thetimes.co.uk/article/edinburgh-professor-gave-names-to-fake-russia-spy-68n2n3bzj
https://www.inopressa.ru/article/26Mar2021/wsj/bulgaria.html
https://www.inopressa.ru/article/26Mar2021/sueddeutsche/spiesser.html
https://www.wsj.com/articles/how-an-alleged-russianspyring-used-cold-war-tactics-11616701381
https://www.sueddeutsche.de/meinung/russland-putin-nawalny-unterdrueckung-1.5246649?reduced=true
https://www.rosbalt.ru/moscow/2021/03/24/1893444.html
https://www.inopressa.ru/article/23Mar2021/nzz/bulgarien.html