https://www.bancaditalia.it/pubblicazioni/quaderni-storia/2020-0046/QSE-46.pdf
https://openknowledge.worldbank.org/bitstream/handle/10986/36647/What-Has-Been-the-Impact-of-COVID-19-on-Debt-Turning-a-Wave-into-a-Tsunami.pdf?sequence=1&isAllowed=y
https://www.propublica.org/article/how-private-nonprofits-ultrawealthy-tax-deductions-museums-foundation-art
http://The Hamburg G-20 summit: Reshaping the economy to serve people and society