L. Pimentel, J., & U. Enock, O. (2019). The Effect of Retention Interval Over a Three Year Period on the Elementary Algebra Performance of High School Students. International Journal of Sciences: Basic and Applied Research (IJSBAR), 43(2), 181–194. Retrieved from https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/9789