Izwar lubis, Selamat Triono , Ambiyar. “VALIDITY OF PRODUCT ON THE DEVELOPMENT OF COMPASS, OBSERVATION, DEMONSTRATION, EVALUATION (CODE) TRAINING MODEL”. Turkish Journal of Computer and Mathematics Education (TURCOMAT) 12, no. 12 (August 28, 2021): 4753–4763. Accessed September 12, 2025. https://textitlejournal.com/turcomat.org/index.php/turkbilmat/article/view/10722.