https://www.ecb.europa.eu/pub/pdf/other/ecb.escblegalconferenceproceedings201812.en.pdf
https://www.ecb.europa.eu/pub/pdf/ecbu/eb201703.en.pdf?ea7747ab0ef3b038300a8d51a3a95313
https://www.aier.org/article/french-exports-to-avoid-wealth-taxes/
https://www.socialeurope.eu/2017/06/understanding-productivity-puzzle/