http://www.europarl.europa.eu/RegData/etudes/IDAN/2017/599352/EPRS_IDA%282017%29599352_EN.pdf
http://www.icaew.com/-/media/corporate/files/technical/economy/brexit/eu-exit-charge.ashx
https://www.sussex.ac.uk/webteam/gateway/file.php?name=briefing-paper-1.pdf&site=18
https://blogs.lse.ac.uk/brexit/2020/10/22/the-cost-of-brexit-is-likely-to-be-more-than-double-that-of-covid-it-must-be-delayed/