Sunanta P, Pansa B, Srakaew PN. The Four Iddhipada – Based English Speaking Instructional System for Students’ Secondary School in Phrae Province. Mahachulalongkornrajavidyalaya University [internet]. 2024 Dec. 31 [cited 2025 Apr. 30];5(3):269-80. available from: https://so10.tci-thaijo.org/index.php/jote/article/view/1866