
https://www.fraserinstitute.org/sites/default/files/economic-freedom-of-the-world-2021.pdf

http://www.cesifo-group.de/portal/page/portal/DocBase_Service/studien/Studie-2017-Felbermayr-etal-Brexit-79843.pdf

https://www.consilium.europa.eu/media/45109/210720-euco-final-conclusions-en.pdf