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

https://www.instituteforgovernment.org.uk/explainers/eu-withdrawal-bill-amendments-and-debates

https://www.bloomberg.com/news/articles/2019-09-11/world-s-oldest-customs-union-and-u-k-reach-a-post-brexit-deal