http://www.cer.eu/sites/default/files/pb_ireland_brexit_6.7.17.pdf
http://fedtrust.co.uk/our-work-on-europe/brexit-heading-to-a-deal-or-no-deal-while-uk-politics-implodes/
http://www.res.org.uk/view/art4Apr17Features.html
http://fedtrust.co.uk/views-from-the-federal-trust/free-movement-and-migration/