https://ec.europa.eu/info/system/files/efb_assessment_of_euro_area_fiscal_stance.pdf
http://www.imf.org/external/np/seminars/eng/2015/secularstag/pdf/Venkateswaran.pdf
https://www.exact.com/benl/downloads/finance/whitepaper-cijfers-altijd-het-antwoord
https://www.imk-boeckler.de/download-proxy-for-faust/download-pdf?url=http%3A%2F%2F217.89.182.78%3A451%2Fabfrage_digi.fau%2Fp_imk_pb_98_2020.pdf%3Fprj%3Dhbs-abfrage%26ab_dm%3D1%26ab_zeig%3D9110%26ab_diginr%3D8482