http://www.consilium.europa.eu/en/press/press-releases/2017/04/29-euco-brexit-guidelines/
http://carnegieeurope.eu/strategiceurope/72634?lang=en
https://www.gov.uk/guidance/status-of-eu-nationals-in-the-uk-what-you-need-to-know
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1714en.pdf