
https://publications.parliament.uk/pa/cm200203/cmhansrd/vo021126/debtext/21126-17.htm

https://www.gov.uk/government/news/david-davis-closing-remarks-at-the-end-of-the-fourth-round-of-eu-exit-negotiations-in-brussels

http://blogs.lse.ac.uk/brexit/2018/05/15/switzerland-wanted-more-immigration-controls-but-economic-self-interest-will-probably-prevail/