https://www.economiesuisse.ch/de/artikel/ohne-schuldenbremse-droht-die-schuldenspirale
https://www.socialeurope.eu/the-european-investment-banks-roadmap-to-2008
https://www.brookings.edu/wp-content/uploads/2024/03/3_Arslanalp-et-al_unembargoed.pdf
https://www.nao.org.uk/wp-content/uploads/2018/01/PFI-and-PF2.pdf