https://science.sciencemag.org/content/365/6448/70
http://www.institutdelors.eu/media/europeidentitemythes-bouchard-ijd-dec16.pdf?pdf=ok
http://futurion.se/wp-content/uploads/2018/03/Futurion_Rapport_2018-1_webb.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