https://www.economiesuisse.ch/de/artikel/ohne-schuldenbremse-droht-die-schuldenspirale
http://www.economics-ejournal.org/economics/journalarticles/2017-10
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/966868/BUDGET_2021_-_web.pdf
http://www.cesifo-group.de/portal/page/portal/DocBase_Service/studien/Studie-2017-Felbermayr-etal-Brexit-79843.pdf