https://blogs.lse.ac.uk/brexit/2019/06/26/did-we-ever-really-understand-how-the-eu-works/
https://ukandeu.ac.uk/wp-content/uploads/2020/05/UKICE-Post-Brexit-Gov-NI-Report.pdf
http://cdn.budgetresponsibility.org.uk/July_2017_Fiscal_risks.pdf
http://openeurope.org.uk/today/blog/will-brexit-ground-flights-europe/