http://fedtrust.co.uk/the-2017-general-election-a-mandate-for-brexit/
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/682894/Draft_Text_for_Discussion_-_Implementation_Period__1_.pdf
https://www.gov.uk/government/news/david-davis-closing-remarks-at-the-end-of-the-fourth-round-of-eu-exit-negotiations-in-brussels
http://carnegieeurope.eu/2017/06/15/bringing-brexit-back-to-reality-pub-71262