https://www.socialeurope.eu/2017/07/german-wages-need-rise/
https://www.cer.eu/sites/default/files/insight_JS_JP_17.1.23.pdf
http://www.bsa.natcen.ac.uk/latest-report/british-social-attitudes-34/key-findings/context.aspx?_ga=2.25464057.552181158.1498632950-1412959047.1496247036
https://www.ccomptes.fr/system/files/2019-07/20190716-rapport-regimes-speciaux-retraite.pdf