Rueksanan N. Development of a Learning Management Model Using a Phenomenon-Based Concept to Enhance Systematic Thinking for Upper Elementary School Students. Saengtham Coll. J. [internet]. 2025 Dec. 30 [cited 2026 Sep. 3];17(2):63-81. available from: https://so01.tci-thaijo.org/index.php/scj/article/view/271253