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/
https://wiiw.ac.at/the-berlin-process-for-the-western-balkans-four-recommendations-to-achieve-progress-n-582.html
https://visegradinsight.eu/viktor-orbans-latest-move/