https://www.dsgv.de/newsroom/presse/190912_PM_EZB_30.html
https://www.boeckler.de/pdf/p_imk_report_139_2018.pdf
https://c24215cec6c97b637db6-9c0895f07c3474f6636f95b6bf3db172.ssl.cf1.rackcdn.com/interactives/2018/tiger/assets/2018-04/2018-04-tiger-total.pdf
https://www.ecb.europa.eu/pub/pdf/ecbu/eb201703.en.pdf?ea7747ab0ef3b038300a8d51a3a95313