Sánchez Fernández, C. A Study on Strategies for Differentiation in the Teaching of English As a Foreign Language. QURRICULUM - Revista De Teoría, Investigación Y Práctica Educativa, n.º 27, Oct. 2017, pp. 29-53, https://www.ull.es/revistas/index.php/qurriculum/article/view/44.