Helda, Trisna, Atmazaki, and Erizal Gani. “The Validity and Practicality of Discovery-Group Learning Models to Improve 21st Century Skills of High School Students”. rEFLections 31, no. 3 (December 26, 2024): 1408–1433. accessed September 30, 2026. https://so05.tci-thaijo.org/index.php/reflections/article/view/277735.