Tasya Natali Sihombing, and Pargaulan Siagian. 2023. “Improving Learning Outcomes Of Class X Students In Mathematics Learning At SMA Negeri 2 Medan Through The Group Investigation (GI) Type Cooperative Model”. JURNAL RISET RUMPUN ILMU PENDIDIKAN 2 (2):182-98. https://doi.org/10.55606/jurripen.v2i2.1585.