Alharbi, M. H., Alwabel, A. S. A., Alohali, M., Almalki, A. M., Othman, M. F. I., Ahmad, M. N. (2026). A hierarchical transformer–graph framework for explainable student engagement estimation in E-learning videos. Scientific Reports. https://doi.org/10.1038/s41598-026-52123-4