Mangwende, Edmore, and Silvanos Chirume. “An APOS Analysis of Preservice Mathematics teachers’ Understanding of Limits of Trigonometric Functions”. JRAMathEdu (Journal of Research and Advances in Mathematics Education) 10, no. 4 (October 31, 2025): 240–253. Accessed January 19, 2026. https://journals2.ums.ac.id/jramathedu/article/view/10440.