https://www.hamiltonproject.org/assets/files/UnionsEA_Web_8.19.pdf
https://www.ilo.org/wcmsp5/groups/public/—ed_norm/—relconf/documents/meetingdocument/wcms_624037.pdf
https://eur-lex.europa.eu/eli/dir/2019/1152/oj
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1714en.pdf