A. A. A. Callanta, A. U. Cubillas, L. O. Engente, and R. L. Liones, “DEVELOPMENT AND VALIDATION OF OUTCOME-BASED INSTRUCTIONALMATERIALS (OBIMs) IN MATHEMATICS 2”, IJEE, vol. 8, no. 2, pp. 240–250, Apr. 2019, Accessed: Oct. 05, 2026. [Online]. Available: https://ijee.org/ijee/article/view/501