Fernandez, J., and O. L. Herrera. “The Effect of Two Different Attentional Focus Techniques on Elementary Non-Athletes Students”. Lecturas: Educación Física Y Deportes, Vol. 23, no. 249, Feb. 2019, pp. 31-41, https://efdeportes.com/efdeportes/index.php/EFDeportes/article/view/611.