Torres Guerrero, Juan, Juan Palomares Cuadros, Elisa Torres Ramos, and Deysy Margarita Pérez Pérez. 2008. “The Methodological Triangulation in Research in Education Sciences”. Avances En Supervisión Educativa, no. 9 (October). https://avances.adide.org/index.php/ase/article/view/334.