https://www.unhcr.org/gcr/GCR_English.pdf
http://www.migrationobservatory.ox.ac.uk/resources/reports/unsettled-status-which-eu-citizens-are-at-risk-of-failing-to-secure-their-rights-after-brexit/
https://www.llri.lt/wp-content/uploads/2018/06/Labour-Migration_3.pdf
https://www.socialeurope.eu/why-europes-migration-crisis-starts-in-africa