Dorimana A, Uworwabayeho A, Nizeyimana G. Enhancing Upper Secondary Learners’ Problem-solving Abilities using Problem-based Learning in Mathematics. IJLTER [Internet]. 2022 Aug. 30 [cited 2026 Jan. 31];21(8):235-52. Available from: http://www.ijlter.myres.net/index.php/ijlter/article/view/1391