The special agreement for immigrants and its impact on the determination of the regulatory basis in pensions calculated pro rata according to Regulation EC 883/2004. Comments on the Judgment of the Court of Justice of the European Union of 28 June 2018, Case C-2/17 Crespo Rey. Revista de Derecho de la Seguridad Social, Laborum, n. 18, p. 179–195, 4 Mar.2019.