Tasya Natali Sihombing, Pargaulan Siagian. Improving Learning Outcomes Of Class X Students In Mathematics Learning At SMA Negeri 2 Medan Through The Group Investigation (GI) Type Cooperative Model. JURRIPEN [Internet]. 2023 Jul. 26 [cited 2024 May 22];2(2):182-98. Available from: https://prin.or.id/index.php/JURRIPEN/article/view/1585