Student attrition in posgraduate blended programs at the Universidad Estatal a Distancia (UNED), Costa Rica: Desertion or delay? UNED Res. J. [Internet]. 2009 Dec. 1 [cited 2026 Sep. 23];1(2):141-9. Available from: https://revistas.uned.ac.cr/index.php/cuadernos/article/view/227