https://www.ifs.org.uk/publications/10302
http://fedtrust.co.uk/our-work-on-europe/there-may-be-trouble-ahead-brexit-after-the-election/
https://institute.global/news/brexit-what-we-now-know
https://ec.europa.eu/commission/publications/terms-reference-article-50-treaty-european-union-negotiations_en