https://www.kcl.ac.uk/policy-institute/assets/uk-attitudes-to-immigration-1018742pub01-115.pdf
https://ippedico.github.io/website/ABIP_entrepreneurship_drain.pdf
https://www.economiesuisse.ch/de/artikel/kuendigungsinitiative-ii-eine-wohlstandsbremse-par-excellence
http://carnegieeurope.eu/strategiceurope/72634?lang=en