https://www.esri.ie/sites/default/files/media/file-uploads/2020-02/DOCiardha%20ESRI%2018%2002.pdf
https://www.sciencespo.fr/cevipof/sites/sciencespo.fr.cevipof/files/CEPR-DP13103.pdf
https://www.socialeurope.eu/2017/06/the-case-for-an-investment-state/
https://www.brookings.edu/articles/increasing-ssi-benefits-is-a-more-effective-approach-to-reducing-poverty-than-an-enhanced-social-security-minimum-benefit/