https://publications.parliament.uk/pa/cm201719/cmselect/cmbeis/380/380.pdf
https://publications.parliament.uk/pa/cm201719/cmselect/cmcumeds/365/36503.htm
https://www.socialeurope.eu/wp-content/uploads/2018/05/BP1-Devolution.pdf
http://www.cer.eu/sites/default/files/pb_ireland_brexit_6.7.17.pdf