Lumbantobing, Irene Vania. 2018. “THE INFLUENCE OF THE NUMBERED HEADS TOGETHER TYPE COOPERATIVE LEARNING MODEL ON STUDENT LEARNING OUTCOMES”. REKOGNISI : Jurnal Pendidikan Dan Kependidikan (E-ISSN 2599-2260) 3 (2):120-29. https://jurnal.unusu.ac.id/index.php/rekognisi/article/view/105.