Sangsuwan W, Prasongsuk K. THE GUIDELINES FOR INTERNAL QUALITY ASSURANCE OPERATION OF SINGHANATRACHALAI SCHOOL GROUP UNDER MAE HONG SON PRIMARY EDUCATIONAL SERVICE AREA OFFICE 1. SN Grad J. [internet]. 2026 Mar. 30 [cited 2026 Oct. 13];23(100):131-45. available from: https://so02.tci-thaijo.org/index.php/SNGSJ/article/view/277327