https://www.ilo.org/wcmsp5/groups/public/—dgreports/—cabinet/documents/publication/wcms_662442.pdf
https://blogs.lse.ac.uk/europpblog/2021/07/23/same-legal-status-but-unequal-treatment-bureaucratic-discrimination-against-mobile-eu-citizens/
https://www.ilo.org/legacy/english/inwork/cb-policy-guide/declarationofPhiladelphia1944.pdf
http://economics.mit.edu/files/12979