1.
Syamsuri S, Purwanto P, Subanji S, Irawati S. Using APOS Theory Framework: Why Did Students Unable To Construct a Formal Proof?. Int. J. Emerg. Math. Educ. [Internet]. 2017 Aug. 24 [cited 2024 Nov. 4];1(2):135-46. Available from: https://journal.uad.ac.id/index.php/IJEME/article/view/5659