https://www.ipg-journal.de/regionen/global/artikel/detail/vorbei-mit-der-freiwilligkeit-4508/
https://www.socialeurope.eu/marrying-labour-flexibility-protection
https://www.instituteforgovernment.org.uk/sites/default/files/publications/IFGJ5327_Report_Brexit_Civil_Service_080317_WEB.pdf
https://www.socialeurope.eu/2017/06/world-imbalances-decline-wages/