https://www.publications.parliament.uk/pa/cm201617/cmselect/cmexeu/1125/1125.pdf
https://www.opendemocracy.net/uk/looking-at-lexit/guy-aitchison/borders-open-borders-or-no-borders?utm_source=Daily+Newsletter&utm_campaign=0a51e05bcc-DAILY_NEWSLETTER_MAILCHIMP&utm_medium=email&utm_term=0_717bc5d86d-0a51e05bcc-407405485
https://uk.yahoo.com/news/brexit-still-wont-happen-says-legal-expert-claimed-article-50-never-triggered-104433721.html
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/621848/60093_Cm9464_NSS_SDR_Web.pdf