https://www.bundeskanzler.de/bk-de/aktuelles/scholz-rede-prag-karls-uni-2079410
https://europa.eu/european-union/about-eu/countries_en
http://www.elperiodico.com/es/politica/20171226/que-es-tabarnia-propuesta-secesion-barcelona-tarragona-resto-cataluna-6517873
https://cdn.ceps.eu/wp-content/uploads/2023/09/2023_17_Potential-Impact-of-Ukrainian-Accession-on-the-EUs-Budget.pdf