https://www.dsgv.de/newsroom/presse/190912_PM_EZB_30.html
https://www.tandfonline.com/doi/full/10.1080/09692290.2022.2107043
http://visual.ons.gov.uk/trading-places-uk-goods-trade-with-eu-partners/
https://theconversation.com/bulgaria-is-joining-the-euro-in-january-and-not-everyone-is-pleased-258626