SIMAN, Michael. Equality Through Differentiation: Opt-Outs and Enhanced Cooperation as Expressions of Sovereignty. In: SEHNÁLEK, David (ed.). Unequal Equals? The Status of Member States in an Integrating European Union. Miskolc–Budapest: Studies of the Central European Professors’ Network,2026. p. 235–277. DOI: 10.54237/profnet.2026.dsuesmsieu_7. Disponível em: https://books.ceapublishing.hu/index.php/ceaprofnet/catalog/book/65/chapter/702. Acesso em: 13 aug. 2026.