https://www.brookings.edu/articles/the-hutchins-center-explains-the-neutral-rate-of-interest/
http://www.ips-journal.eu/regions/global/article/show/davos-2018-call-the-doctor-2544/
https://www.economiesuisse.ch/de/artikel/ohne-schuldenbremse-droht-die-schuldenspirale