https://www.boeckler.de/pdf/p_wsi_report_39e_2018.pdf
https://www.etui.org/sites/default/files/2021-12/01-ETU%20BM2021-Small.pdf
https://www.etui.org/content/download/36217/363575/file/F-B_07_EN_WEB.pdf
https://eur-lex.europa.eu/eli/dir/2019/1152/oj