https://www.ecb.europa.eu/press/key/date/2012/html/sp120726.en.html
https://www.reuters.com/world/europe/germanys-government-looks-inward-challenges-mount-allies-fret-2022-12-08/
https://blogs.lse.ac.uk/brexit/2019/12/03/a-missed-opportunity-revisiting-the-euro-referendum-that-never-was-from-a-historical-perspective/
http://www.sgi-network.org/2017/About