G. Esparó, M. Torrente, J. D. Fernández-ballart, y J. Canals, «Psychological problems and associated factors at 6 years of age: Differences between sexes»., Span. j. psychol., vol. 7, n.º 1, pp. 53–62, abr. 2004, Accedido: jul. 22, 2026. Disponible en: https://revistas.ucm.es/index.php/SJOP/article/view/SJOP0404120053A