http://www.cer.eu/sites/default/files/pb_ireland_brexit_6.7.17.pdf
https://socialeurope.eu/brexit-why-does-northern-ireland-matter-so-much
https://www.gov.uk/government/news/pms-open-letter-to-eu-citizens-in-the-uk
https://www.brookings.edu/blog/order-from-chaos/2018/01/05/the-brexit-options-explained/?utm_campaign=Brookings%20Brief&utm_source=hs_email&utm_medium=email&utm_content=59815275