เพ็ญกุลกิจ ร, ไทยใจดี ย. Instructional Leadership of School Administrators under the Secondary Educational Service Area Office 21. J Roi Et [internet]. 2017 Dec. 31 [cited 2026 Sep. 12];11(2):154-62. available from: https://so03.tci-thaijo.org/index.php/reru/article/view/176358