https://www.ajot.com/news/the-brexit-checklist-where-the-u.k.-and-eu-currently-stand
https://www.un.org/esa/population/publications/migration/migration.htm
http://oegfe.at/wordpress/2017/05/the-free-movement-of-workers-within-the-eu-and-the-case-of-austria-balancing-distortions-and-adding-value-op-ed-paul-schmidt-the-european-financial-review/
https://www.aicgs.org/publication/refugees-terrorism-and-a-failing-security-architecture/