http://www.niesr.ac.uk/sites/default/files/publications/NIESR%20EU2%20MIGRATION%20REPORT.pdf
https://www.socialeurope.eu/2017/06/answer-wages-not-capital/
http://fedtrust.co.uk/views-from-the-federal-trust/free-movement-and-migration/
https://reliefweb.int/attachments/66a09358-2cf3-448c-846a-d29f9f8f768c/62a9d1494.pdf