https://www.nao.org.uk/wp-content/uploads/2018/10/The-UK-border-preparedness-for-EU-exit.pdf
https://publications.parliament.uk/pa/ld201719/ldselect/ldconst/69/69.pdf
https://www.bloomberg.com/news/articles/2017-06-01/soros-says-brexit-may-last-5-years-and-cause-immense-damage?cmpid=BBBXT060217_BIZ&utm_medium=email&utm_source=newsletter&utm_term=170602&utm_campaign=brexit
https://ec.europa.eu/commission/publications/terms-reference-article-50-treaty-european-union-negotiations_en