https://www.gov.uk/guidance/status-of-eu-nationals-in-the-uk-what-you-need-to-know
http://www.ecfr.eu/page/-/Keeping_Europe_Safe_After_Brexit2.pdf
https://publications.parliament.uk/pa/cm201719/cmselect/cmcumeds/365/365.pdf
https://www.socialeurope.eu/wp-content/uploads/2018/05/BP1-Devolution.pdf