https://ecfr.eu/wp-content/uploads/How-to-prevent-Germany-from-becoming-Eurosceptic.pdf
https://www.eeas.europa.eu/eeas/ukraine-statement-high-representative-josep-borrell-illegal-%E2%80%9Creferenda%E2%80%9D-luhansk-kherson-and_en
https://happiness-report.s3.amazonaws.com/2020/WHR20.pdf
https://www.koerber-stiftung.de/fileadmin/user_upload/koerber-stiftung/redaktion/the-berlin-pulse/pdf/2018/The-Berlin-Pulse-2018.pdf