https://www.economiesuisse.ch/de/artikel/ohne-schuldenbremse-droht-die-schuldenspirale
http://www.imf.org/external/np/seminars/eng/2015/secularstag/pdf/Venkateswaran.pdf
https://publications.parliament.uk/pa/cm201719/cmselect/cmpubacc/1793/1793.pdf
https://www.esri.ie/system/files/publications/WP677_0.pdf