Mendez, Fernando, Mario Mendez, y Vasiliki Vasiliki Triga Triga. 2020. «Direct Democracy in the European Union: How Comparative Federalism Can Help Us Understand the Interplay of Direct Democracy and European Integration». Revista De Ciencia Política 29 (1):57-83. https://doi.org/10.4067/S0718-090X2009000100003.