https://rusi.org/explore-our-research/publications/commentary/nato-vilnius-summit-bucharest-20
https://www.koerber-stiftung.de/fileadmin/user_upload/koerber-stiftung/redaktion/the-berlin-pulse/pdf/2018/The-Berlin-Pulse-2018.pdf
https://www.ips-journal.eu/topics/european-integration/stepping-out-of-russias-sphere-of-influence-6759/
https://rusi.org/sites/default/files/by_parity_and_presence_final_web_version.pdf