https://www.ipg-journal.de/regionen/global/artikel/detail/vorbei-mit-der-freiwilligkeit-4508/
http://economics.mit.edu/files/12979
http://www.oecd.org/fr/emploi/emp/Editorial-and-executive-summary-FR.pdf
https://www.opendemocracy.net/en/pandemic-border/keeping-italian-agri-food-system-alive-migrant-farmworkers-wanted/