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. revsegsoc [Internet]. 2026 Mar. 30 [cited 2026 Nov. 6];(46):121-30. Available from: https://revista.laborum.es/index.php/revsegsoc/article/view/1277