https://www.hamiltonproject.org/assets/files/UnionsEA_Web_8.19.pdf
https://www.ips-journal.eu/topics/democracy-and-society/german-companies-have-to-ensure-decent-working-conditions-5013/
http://www.niesr.ac.uk/sites/default/files/publications/Facing%20the%20Future%20Tackling%20post-Brexit%20Labour%20and%20skills%20NIESR.CIPD_.pdf
https://www.publications.parliament.uk/pa/ld201314/ldselect/ldeucom/164/164.pdf