http://ec.europa.eu/finance/docs/law/171011-communication-banking-union_en.pdf
https://www.socialeurope.eu/the-frugal-four-should-save-the-european-project
https://www.brookings.edu/articles/why-the-founders-cared-about-trade-and-taxes/
https://www.boeckler.de/pdf/p_imk_study_58_2018.pdf