http://www.migrationobservatory.ox.ac.uk/resources/reports/unsettled-status-which-eu-citizens-are-at-risk-of-failing-to-secure-their-rights-after-brexit/
http://blogs.lse.ac.uk/brexit/2018/05/15/switzerland-wanted-more-immigration-controls-but-economic-self-interest-will-probably-prevail/
http://ukandeu.ac.uk/wp-content/uploads/2017/06/One-year-on.pdf