https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1747en.pdf
https://blogs.lse.ac.uk/europpblog/2021/07/23/same-legal-status-but-unequal-treatment-bureaucratic-discrimination-against-mobile-eu-citizens/
https://eur-lex.europa.eu/eli/dir/2019/1152/oj
https://www.boeckler.de/pdf/p_imk_report_141e_2018.pdf