Alsina i Pastells, Àngel. “WHY DO SOME CHILDREN HAVE DIFFICULTY CALCULATING? AN APPROACH FROM THE STUDY OF HUMAN MEMORY”. Revista Latinoamericana de Investigación en Matemática Educativa, vol. 10, no. 3, Aug. 2007, pp. 315-33, https://www.relime.org/index.php/relime/article/view/369.