Fortin Morales, Alvaro M., Fons J. R. van de Vijver, and Ype H. Poortinga. “Differential Item Functioning and Educational Risk Factors in Guatemalan Reading Assessment”. Revista Interamericana de Psicología/Interamerican Journal of Psychology 47, no. 3 (October 9, 2014). Accessed April 5, 2026. http://sip2013.sipsych.org/ojs-/index.php/IJP/article/view/236.