https://blogs.lse.ac.uk/brexit/2019/10/09/northern-ireland-depends-on-the-eus-fluid-borders-for-survival/
http://www.elysee.fr/declarations/article/transcription-du-discours-du-president-de-la-republique-au-forum-economique-mondial-de-davos-suisse/
https://institutdelors.eu/wp-content/uploads/2021/10/BP_211006_La-primaute-du-droit-de-lUnion-europeenne_Omnes.pdf