Vebianti FM, Sunardi, Suwito A, Trapsilasiwi D, Oktavianingtyas E. Analysis of Geometry Problem Solving Based on APOS Theory for Class IX Students. JELMaR [Internet]. 2022 May 11 [cited 2026 Aug. 25];3(1):33-41. Available from: https://jelmar.wisnuwardhana.ac.id/index.php/jelmar/article/view/108