https://www.aspistrategist.org.au/is-the-europen-union-too-big-for-further-enlargement/
https://ec.europa.eu/commission/sites/beta-political/files/seminar-20200114-lpf_en.pdf
https://socialeurope.eu/who-guards-the-guardians-in-europe
https://blogs.lse.ac.uk/brexit/2021/02/04/indyref2-scottish-independence-would-be-2-3-times-more-costly-than-that-of-brexit-and-rejoining-the-eu-wouldnt-make-up-the-difference/