Martínez Fernández, Reinaldo, et al. “USEFULNESS OF DIFFERENT HINTS IN SOLVING AN INSIGHT PROBLEM: RELATION-SHIP WITH METACOGNITIVE STRATEGIES”. Anales De Psicología Annals of Psychology, vol. 24, no. 1, Jan. 2008, pp. 16-24, https://revistas.um.es/analesps/article/view/31661.