http://ec.europa.eu/trade/policy/in-focus/ceta/
https://ec.europa.eu/commission/sites/beta-political/files/customs_controls_0.pdf
http://ecipe.org/publications/the-uks-first-international-trade-negotiation/?chapter=all
http://www.esf.be/new/wp-content/uploads/2018/07/ESF-Press-Release-on-Importance-of-Services-Trade-in-EU-UK-Future-Relastionship.pdf
https://www.wto.org/english/thewto_e/whatis_e/tif_e/understanding_e.pdf
https://institute.global/news/customs-and-exiting-european-union
https://home.kpmg.com/content/dam/kpmg/nl/pdf/2018/sector/overheid/impact-van-non-tarifaire-handelsbelemmeringen-als-gevolg-van-brexit.pdf
https://www.wto.org/english/news_e/pres18_e/pr820_e.htm
http://www.cbi.org.uk/index.cfm/_api/render/file/?method=inline&fileID=7C026F7C-746E-4795-90EFCC69B2FB6756
https://www.iod.com/Portals/0/PDFs/Campaigns%20and%20Reports/Europe%20and%20trade/Going-global.pdf?ver=2018-04-04-164140-840