https://www.socialeurope.eu/2017/05/europe-en-marche/
https://www.brookings.edu/articles/the-difference-in-how-the-wealthy-make-money-and-pay-taxes/
https://www.econstor.eu/bitstream/10419/283282/1/1877510009.pdf
https://www.iwh-halle.de/fileadmin/user_upload/publications/gd/2022f/GD_F22_Langfassung_online.pdf