
http://fedtrust.co.uk/views-from-the-federal-trust/free-movement-and-migration/

https://publications.parliament.uk/pa/ld201719/ldselect/ldeucom/9/9.pdf

https://www.theguardian.com/politics/2017/nov/10/brexit-date-is-not-irreversible-says-man-who-wrote-article-50-lord-kerr