http://carnegieeurope.eu/2017/06/15/bringing-brexit-back-to-reality-pub-71262
https://www.esri.ie/system/files/publications/RB202017_2.pdf
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/652285/Joint_Ministerial_Committee_communique.pdf
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/640485/Technical_note_on_Functionality_and_Protocol_7.pdf