“The extreme legal complexity of administrative files to which the European Union regulations on the coordination of the national social security systems of the member states apply: An inductive analysis of Portuguese case law compared with Spanish law on the subject” (2026) Revista de Derecho de la Seguridad Social, Laborum, (46), pp. 121–130. Available at: https://revista.laborum.es/index.php/revsegsoc/article/view/1277 (Accessed: 6 November 2026).