https://www.euronews.com/2018/09/25/why-is-the-irish-border-issue-so-complex-euronews-answers
https://www.bloomberg.com/news/articles/2017-06-14/ryanair-easyjet-say-soft-brexit-won-t-address-airline-concerns?cmpid=BBBXT061517_BIZ&utm_medium=email&utm_source=newsletter&utm_term=170615&utm_campaign=brexit
http://blogactiv.eu/blog/2012/05/15/stumbling-towards-the-brexit/
http://blogs.lse.ac.uk/brexit/2017/07/06/the-1bn-bung-wont-protect-northern-ireland-from-the-pain-of-a-hard-brexit/