https://www.ipg-journal.de/rubriken/europaeische-integration/artikel/maechtig-maechtiger-eu-kommission-6567/
https://www.brookings.edu/articles/the-changing-role-of-the-us-dollar/
https://blogs.lse.ac.uk/europpblog/2021/10/22/de-facto-differentiation-in-action-why-poland-will-stay-in-the-eu-with-or-without-the-blessing-of-brussels/