Hermana R. Improving Critical Thinking Skills Through Problem-Based Learning Assited by Youtube for Class XI IPS Students of SMAN 1 West Sumatra. langgam [Internet]. 18Nov.2023 [cited 1Feb.2025];1(04):21-. Available from: http://langgam.ppj.unp.ac.id/index.php/jurnal/article/view/28