http://sprc.info/wp-content/uploads/2012/07/Polish-Migrants-in-London-extending-the-stay.pdf
https://www.esri.ie/system/files/publications/JR1.pdf
https://www.socialeurope.eu/2017/07/time-eu-fair-movement-directive/
http://www.britishchambers.org.uk/press-office/press-releases/bcc-firms-invest-in-local-labour-but-still-need-foreign-skills-to-plug-shortages.html