P. Kiriakidis, J. W. Decosta, și A. Sandu, „What is the effect of grade point average (GPA) on courses taken either face-to-face or online by undergraduate working adult students?”, rcis, vol. 33, pp. 7–26, iun. 2011, Data accesării: nov. 07, 2026. Disponibil la: https://www.rcis.ro/journal/article/view/338-what-is-the-effect-of-grade-point-average-gpa-on-courses