http://www.oxera.com/Latest-Thinking/Publications/Reports/2017/Brexit-ports.aspx
http://www.consilium.europa.eu//media/32504/xt21004-ad01re02en18.pdf
http://www.icaew.com/-/media/corporate/files/technical/economy/brexit/eu-exit-charge.ashx
http://www.lawsociety.org.uk/news/stories/leaving-in-an-orderly-fashion-our-approach-to-brexit/