https://www.ips-journal.eu/topics/foreign-and-security-policy/security-in-limbo-7255/
http://www.cepii.fr/PDF_PUB/pb/2021/pb2021-36.pdf
https://www.socialeurope.eu/ukraine-war-zelenskyys-very-risky-move
https://theconversation.com/la-anomalia-empirica-de-las-elecciones-en-argentina-donde-dos-mas-dos-no-suman-cuatro-217319