https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef18001en.pdf
http://library.fes.de/pdf-files/dialog/13464.pdf
https://www.ips-journal.eu/topics/democracy-and-society/german-companies-have-to-ensure-decent-working-conditions-5013/
https://www.hamiltonproject.org/assets/files/UnionsEA_Web_8.19.pdf