https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1663en.pdf
https://www.ilo.org/wcmsp5/groups/public/@dgreports/@dcomm/documents/briefingnote/wcms_743146.pdf
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1729en.pdf