https://www.socialeurope.eu/the-frugal-four-should-save-the-european-project
https://www.nber.org/system/files/working_papers/w28598/w28598.pdf
http://invs.santepubliquefrance.fr/publications/etat_sante_2017/ESP2017_Synthese.pdf
https://www.bruegel.org/sites/default/files/2022-11/PC%2020%202022_4.pdf