https://blogs.lse.ac.uk/brexit/2019/08/12/boris-johnsons-real-agenda-the-singapore-scenario/
http://www.independent.co.uk/news/uk/politics/article-127-brexit-stop-what-is-it-single-market-eu-eea-theresa-may-article-50-a7955806.html
http://www.rug.nl/research/portal/files/41711829/cesifo1_wp6448.pdf
http://www.wsta.co.uk/images/Brexit/Brexit_FINAL.pdf