https://www.sbs.strath.ac.uk/economics/fraser/20170322/FEC-Vol41-No1.pdf
https://committees.parliament.uk/publications/23257/documents/169721/default/
https://www.socialeurope.eu/the-frugal-four-should-save-the-european-project
https://www.dsgv.de/newsroom/presse/190912_PM_EZB_30.html