Luther Tandiarrang. “Improving Learning Outcomes of Pythagorean Theorem Using STAD Cooperative Learning Type for 8th Grade Students at SMPN 1 Rindingallo”. DEIKTIS: Jurnal Pendidikan, Bahasa Dan Sastra, Vol. 1, no. 2, Dec. 2021, pp. 343-52, https://dmi-journals.org/deiktis/article/view/511.