1.
Napitupulu K, Munthe B, Siregar N. The Effect of Reinforcement Skills on Increasing the Learning Motivation of Grade XI Students in Christian Religious Education . PIJAR [Internet]. 2025 Nov. 15 [cited 2026 Apr. 17];4(1):68-79. Available from: https://putrapublisher.org/ojs/index.php/pijar/article/view/1124