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

http://www.niesr.ac.uk/sites/default/files/publications/NIESR%20GE%20Briefing%20Paper%20No.%204%20-%20Agriculture%20in%20the%20UK_0.pdf

https://ec.europa.eu/commission/publications/terms-reference-article-50-treaty-european-union-negotiations_en