https://data.oecd.org/natincome/net-lending-borrowing-by-sector.htm
https://documents-dds-ny.un.org/doc/UNDOC/LTD/N22/622/29/PDF/N2262229.pdf?OpenElement
https://www.socialeurope.eu/germanys-true-economic-disease
https://www.socialeurope.eu/europe-needs-a-public-investment-revolution-to-secure-its-economic-future