Andi Suwarni, and Nurasia Natsir. “The Effectiveness of Project-Based Collaborative Learning in Improving English Speaking Skills of High School Students”. International Journal of Educational Research 1, no. 4 (December 30, 2024): 87–101. Accessed June 15, 2025. https://international.aripi.or.id/index.php/IJER/article/view/283.