https://static1.squarespace.com/static/5afc0bbbf79392ced8b73dbf/t/5b07d7ce1ae6cf2a4178f587/1527240672975/SGC_Full_Report.pdf
https://www.europarl.europa.eu/RegData/etudes/IDAN/2021/699811/IPOL_IDA%282021%29699811_EN.pdf
https://blogs.lse.ac.uk/brexit/2019/12/03/a-missed-opportunity-revisiting-the-euro-referendum-that-never-was-from-a-historical-perspective/