https://socialeurope.eu/brexit-why-does-northern-ireland-matter-so-much
https://publications.parliament.uk/pa/ld5801/ldselect/ldeucom/248/248.pdf
http://fedtrust.co.uk/our-work-on-europe/hard-brexit-international-trade-and-the-wto-scenario/
https://www.socialeurope.eu/2017/07/brexit-to-nowhere/