1. Abdullah, A. H., Fadil, S. S., Tahir, L. M., Abd Rahman, S. N. S., & Hamzah, M. H. (2019). Emerging patterns and problems of higher-order thinking skills (HOTS) mathematical problem-solving in the Form-three assessment (PT3). South African Journal of Education, 39(2), 1–18.
2. Abdullah, A. H., Rahman, S. N. S., & Hamzah, M. H. (2017). Metacognitive skills of Malaysian students in non-routine mathematical problem solving. Bolema, 31(57), 310–322.
3. Akhter, N., & Akhter, N. (2018). Learning in mathematics: Difficulties and perceptions of students. Journal of Educational Research, 21(1), 147–163.
4. Anderson, L. W., Krathwohl, D. R., Airasian, P. W., Cruikshank, K. A., Mayer, R. E., Pintrich, P. R., Raths, J., & Wittrock, M. C. (2001). A taxonomy for learning, teaching, and assessing: A revision of Bloom’s Taxonomy of Educational Objectives (Complete edition). Longman.
5. Azina, I. N., & Halimah, A. (2012). Student factors and mathematics achievement: Evidence from TIMSS 2007. EURASIA Journal of Mathematics, Science and Technology Education, 8(3), 249–255.