Khattapan CN. THE CASE STUDY RESEARCH OF EXAMINING THE USEFULNESS AND PERCEPTION OF THE ONLINE TEACHING PREPARATION PROGRAM: Received: 13th November 2021; Revised: 17th May 2022, 21st May 2022, 24th May 2022; Accepted: 24th May 2022. pijtel [Internet]. 2022 May 25 [cited 2024 Nov. 21];6(1):359-72. Available from: https://grdspublishing.org/index.php/PUPIL/article/view/2007