R. K. Asomah, M. Narh-Kert, S. Abdul-Malik, J. Enu, and A. Koomson, “Evaluation of students’ performance in elective mathematics: The effect of high school students’ perceived difficulty of the subject”, Int. J. Edu. Inno. Res., vol. 3, no. 2, pp. 241–258, Aug. 2024.