https://visegradinsight.eu/moderate-reactivation-weimar-triangle/
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/monthly-report-no-04-2024-dlp-6876.pdf
https://www.eppgroup.eu/download/file/t5F7fWVHAho9XFLF3fGb3HMHOc_fBpiq-JJIhg_2alGxibc6qNgf4Xn7KKgAAAACEQU0OTEyMw