Martín, Elena, Rosario Martínez-arias, Alvaro Marchesi, and Eva M. Pérez. 2008. “Variables that predict academic achievement in the spanish compulsory secondary educational system: a longitudinal, multi-level analysis”. The Spanish Journal of Psychology 11, nº 2:: 400-413. https://revistas.ucm.es/index.php/SJOP/article/view/SJOP0808220400A