https://www.tasc.ie/assets/files/pdf/ensuring_good_future_jobs.pdf
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef18001en.pdf
https://www.strategie.gouv.fr/sites/strategie.gouv.fr/files/atoms/files/coe-rapport-travail-non-declare-fevrier-2019.pdf
http://www.ilo.org/wcmsp5/groups/public/—dgreports/—cabinet/documents/genericdocument/wcms_371208.pdf