https://institute.global/news/customs-and-exiting-european-union
http://www.amchameu.eu/sites/default/files/publications/files/transatlanticeconomy2021_fullreporthr.pdf
https://publications.parliament.uk/pa/bills/cbill/2017-2019/0005/18005.pdf
https://www.elibrary.imf.org/downloadpdf/book/9798400224119/CH004.xml