., Herizal, Marhami ., and Nurul Akmal. “Students’ Errors in Constructing Mathematical Proofs by Direct Method”. KnE Social Sciences 9, no. 13 (April 26, 2024): 651–659. Accessed May 19, 2024. https://knepublishing.com/index.php/KnE-Social/article/view/15969.