https://www.d-kart.de/en/blog/2020/05/11/ultra-vires/
https://euagenda.eu/upload/publications/untitled-124549-ea.pdf
https://www.swp-berlin.org/publications/products/arbeitspapiere/WP_03-2021_EPIN-Report_CoFoE_01.pdf
https://www.project-syndicate.org/commentary/three-goals-to-guide-european-union-renewal-by-emmanuel-macron-2019-03/french