
https://www.opendemocracy.net/en/can-europe-make-it/rest-and-west-thoughts-on-brexit-and-migration-part-one/

https://read.oecd-ilibrary.org/social-issues-migration-health/international-migration-outlook-2018_migr_outlook-2018-en#page1

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/695321/An_inspection_of_exit_checks.pdf