Santia, I., Purwanto, Sutawidjadja, A., Sudirman, & Subanji. (2019). Exploring mathematical representations in solving ill-structured problems: The case of quadratic function. Journal on Mathematics Education, 10(3), 365–378. Retrieved from https://jme.ejournal.unsri.ac.id/index.php/jme/article/view/3800