http://invs.santepubliquefrance.fr/publications/etat_sante_2017/ESP2017_Ouvrage_complet_vdef.pdf
https://www.propublica.org/article/how-private-nonprofits-ultrawealthy-tax-deductions-museums-foundation-art
https://www.esrb.europa.eu/pub/pdf/wp/esrbwp21.en.pdf
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef18001en.pdf