https://www.socialeurope.eu/the-frugal-four-should-save-the-european-project
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_report_159e_2020.pdf%3Fprj%3Dhbs-abfrage%26ab_dm%3D1%26ab_zeig%3D8946%26ab_diginr%3D8482
http://www.ips-journal.eu/regions/global/article/show/davos-2018-call-the-doctor-2544/
https://reformscotland.com/wp-content/uploads/2018/04/The-VAT-opportunity.pdf