Buamul J, Sawangboon T. A Development of Learning Activity based on Problem-Based Learning with Online Media to Promote Collaborative Problem-Solving Competency of Grade 11 students on Topic of Solutions. Ratchaphruek [internet]. 2023 Mar. 28 [cited 2026 Aug. 26];21(1):121-36. available from: https://so05.tci-thaijo.org/index.php/Ratchaphruekjournal/article/view/262586