http://www.rug.nl/research/portal/files/41711829/cesifo1_wp6448.pdf
https://apps.eui.eu/EUI_API/EVENTSV2/Attachments/Index?id=22316
http://blogactiv.eu/blog/2012/05/15/stumbling-towards-the-brexit/
https://uk.reuters.com/article/uk-britain-eu-options/stairway-to-brexit-barnier-maps-out-uks-canadian-path-idUKKBN1ED23R