https://www.rand.org/pubs/research_reports/RR1786.html
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/695321/An_inspection_of_exit_checks.pdf
http://www.guengl.eu/news/article/eu-citizens-rights-and-status-of-north-of-ireland-must-be-prioritised-in-br
http://www.abpi.org.uk/media/4575/uk-exiting-from-eu_life-science-industry-coalition_position-paper.pdf