https://www.socialeurope.eu/why-such-disparity-between-unemployment-rates-in-europe
https://www.ceps.eu/system/files/CEPS%20-%20LINKEDIN%20study%20FINAL.pdf
http://www.ilo.org/wcmsp5/groups/public/—dgreports/—dcomm/—publ/documents/publication/wcms_548950.pdf
https://www.researchgate.net/publication/351524462_HesaMag_23_-_with_a_special_report_about_workers_in_the_food_chain/link/609bfc9b458515a04c638ff6/download