http://www.lecese.fr/sites/default/files/pdf/Fiches/2017/FI13_raef.pdf http://www.lecese.fr/images/colloque/RAEF2017/RAEFVersionSection2.pdf
https://towardsdatascience.com/getting-started-with-r-programming-2f15e9256c9
https://docs.prosperity.com/3616/3544/3967/The_2021_Legatum_Prosperity_Index_Overview_-_Web.pdf