http://www.diw.de/documents/publikationen/73/diw_01.c.562050.de/17-29.pdf
https://mailchi.mp/ecipe/european-election-populism-and-the-future-of-the-eu-trade-policy-newsletter-may-941788?e=286ad5ef5f
https://www.aspistrategist.org.au/is-the-europen-union-too-big-for-further-enlargement/
https://ukandeu.ac.uk/explainers/eu-switzerland-negotiations-agreement/?mc_cid=1b270f9c56&mc_eid=815b1928ec