https://www.ccomptes.fr/system/files/2019-07/20190716-rapport-regimes-speciaux-retraite.pdf
https://www.economiesuisse.ch/de/artikel/globale-umverteilung-der-firmensteuern-mit-fragezeichen
http://www.sgi-network.org/2017/About
https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/earningsandworkinghours/articles/contractsthatdonotguaranteeaminimumnumberofhours/may2017