Hermana, Rina. “Improving Critical Thinking Skills Through Problem-Based Learning Assited by Youtube for Class XI IPS Students of SMAN 1 West Sumatra”. LANGGAM: International Journal of Social Science Education, Art and Culture 1, no. 04 (November 18, 2023): 21-31. Accessed November 15, 2024. http://langgam.ppj.unp.ac.id/index.php/jurnal/article/view/28.