https://policyscotland.gla.ac.uk/blog-sir-ivan-rogers-speech-text-in-full/
http://www.cer.org.uk/sites/default/files/insight_js_st_9.6.17.pdf
http://www.conservativehome.com/thecolumnists/2017/05/christopher-howarths-guide-to-brexit-the-manifesto-must-convince-leavers-and-lock-in-our-escape-from-the-eu.html