
https://dgap.org/system/files/article_pdfs/dgap-report-2023-01-EN-Rethinking%20EUs%20Eastern%20Enlargement_0.pdf

https://blogs.lse.ac.uk/europpblog/2023/10/17/why-differentiation-is-now-at-the-heart-of-europes-political-system/

http://2ihmoy1d3v7630ar9h2rsglp-wpengine.netdna-ssl.com/wp-content/uploads/2019/09/190926-Brexit-and-the-Belfast-Good-Friday-Agreement-Final-report.pdf