https://ec.europa.eu/commission/sites/beta-political/files/guiding-principles-dialogue-ei-ni_en.pdf
https://publications.parliament.uk/pa/cm201719/cmselect/cmsctech/705/70503.htm#_idTextAnchor001
https://publications.parliament.uk/pa/cm201719/cmselect/cmexeu/935/935.pdf
http://ukandeu.ac.uk/brexit-a-french-perspective/