https://www.theguardian.com/politics/2017/sep/04/uk-trade-deals-after-brexit-theresa-may-eu
https://www.friendsofeurope.org/sites/default/files/media-files/uk_report_web.pdf
https://www.iod.com/Portals/0/PDFs/Campaigns%20and%20Reports/Europe%20and%20trade/Business-of-Brexit.pdf?ver=2017-05-22-090428-150
http://www.conservativehome.com/parliament/2016/04/theresa-mays-speech-on-brexit-full-text.html