“Have Alternative Social Security Mutualities to the RETA Reached Their Lowest Point? The Mandatory Inclusion of Self-Employed Professional Groups in the RETA ‘system’ Is Seen As a Logical Step Within the Overall Social Security Framework”. Revista de Derecho de la Seguridad Social, Laborum, no. 39, June 2024, pp. 13-32, https://revista.laborum.es/index.php/revsegsoc/article/view/971.