https://www.socialeurope.eu/progressive-taxation-for-a-renewed-social-contract
http://norden.diva-portal.org/smash/get/diva2:1095959/FULLTEXT02.pdf
https://www.suerf.org/docx/f_ec43638b66e16a5bbede9b710b12b0c7_32333_suerf.pdf
https://www.bancaditalia.it/pubblicazioni/quaderni-storia/2020-0046/QSE-46.pdf