https://www.socialeurope.eu/progressive-taxation-for-a-renewed-social-contract
https://www.socialeurope.eu/wp-content/uploads/2017/06/EURO-web.pdf
https://www.bancaditalia.it/pubblicazioni/quaderni-storia/2020-0046/QSE-46.pdf
https://lawliberty.org/book-review/the-canary-in-the-feds-coal-mine/