Fredy Gavilanes-Sagnay, Edison Loza-Aguirre, Byron Ernesto Vaca Barahona, Henry N. Roa. 2023. “A Systematic Review of Ill-Defined Problems in the Intelligent Tutoring Systems in Virtual Learning Environments”. International Journal of Intelligent Systems and Applications in Engineering 11 (5s):220 -. https://ijisae.org/index.php/IJISAE/article/view/2769.