http://library.fes.de/pdf-files/iez/13375.pdf
https://institute.global/news/customs-and-exiting-european-union
https://freedomhouse.org/sites/default/files/Feb2019_FH_FITW_2019_Report_ForWeb-compressed.pdf
https://www.bruegel.org/wp-content/uploads/2022/02/PC-02.pdf