
https://www.euronews.com/2018/09/25/why-is-the-irish-border-issue-so-complex-euronews-answers

http://www.parliament.uk/documents/commons-committees/Exiting-the-European-Union/17-19/Cross-Whitehall-briefing/EU-Exit-Analysis-Cross-Whitehall-Briefing.pdf

https://lif.blob.core.windows.net/lif/docs/default-source/default-library/170427-final-trade-blueprintweb.pdf?sfvrsn=0