https://www.brookings.edu/wp-content/uploads/2016/07/Full-Report.pdf
https://www.ilo.org/wcmsp5/groups/public/—ed_norm/—relconf/documents/meetingdocument/wcms_624037.pdf
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef20023en.pdf