https://www.ccomptes.fr/system/files/2019-07/20190716-rapport-regimes-speciaux-retraite.pdf
https://www.socialeurope.eu/progressive-taxation-for-a-renewed-social-contract
https://www.socialeurope.eu/how-to-reform-the-european-fiscal-rules
https://www.boeckler.de/pdf/p_wsi_report_52_2019.pdf