https://blogs.lse.ac.uk/europpblog/2023/10/17/why-differentiation-is-now-at-the-heart-of-europes-political-system/
http://www.sinistraliberale.org/files/Manifesto_di_Ventotene_1944.pdf
https://theconversation.com/las-leyes-de-lanchester-guerras-y-ecuaciones-222469