http://ec.europa.eu/economy_finance/publications/pages/publication16004_en.pdf
http://www.cesifo-group.de/portal/page/portal/DocBase_Service/studien/Studie-2017-Felbermayr-etal-Brexit-79843.pdf
https://www.sussex.ac.uk/webteam/gateway/file.php?name=briefing-paper-1.pdf&site=18