https://www.socialeurope.eu/progressive-taxation-for-a-renewed-social-contract
https://www.econstor.eu/bitstream/10419/283282/1/1877510009.pdf
https://www.brookings.edu/articles/the-difference-in-how-the-wealthy-make-money-and-pay-taxes/
https://www.resolutionfoundation.org/app/uploads/2019/11/The-shape-of-things-to-come.pdf