https://www.publications.parliament.uk/pa/ld201617/ldselect/ldeucom/116/116.pdf
http://fedtrust.co.uk/brexitthe-conservative-centre-cannot-hold/
https://blogs.lse.ac.uk/brexit/2019/10/09/northern-ireland-depends-on-the-eus-fluid-borders-for-survival/
https://www.opendemocracy.net/en/opendemocracyuk/customs-union-leaves-everything-play-trade-justice/?utm_source=Daily+Newsletter&utm_campaign=f531c721c4-DAILY_NEWSLETTER_MAILCHIMP&utm_medium=email&utm_term=0_717bc5d86d-f531c721c4-407405485