http://www.ecfr.eu/page/-/ECFR-_245_-_Crisis_and_Cohesion_-_A_10_Year_Review_Janning_WEB.pdf
https://www.foreignaffairs.com/europe/promise-and-peril-eu-expansion
https://ec.europa.eu/commission/presscorner/api/files/document/print/ov/speech_22_5493/SPEECH_22_5493_OV.pdf