https://docs.iza.org/dp16728.pdf
http://europa.eu/rapid/press-release_MEMO-17-2001_en.htm
https://uk.reuters.com/article/uk-britain-eu-options/stairway-to-brexit-barnier-maps-out-uks-canadian-path-idUKKBN1ED23R
https://www.socialeurope.eu/trump-and-brexit