https://www.publications.parliament.uk/pa/ld201314/ldselect/ldeucom/164/164.pdf
http://invs.santepubliquefrance.fr/publications/etat_sante_2017/ESP2017_Ouvrage_complet_vdef.pdf
https://www.brookings.edu/wp-content/uploads/2016/07/Full-Report.pdf
https://ec.europa.eu/social/main.jsp?catId=738&langId=en&pubId=8553