Luo Sai, .The development of training course based on nondirective teaching theory to improve visual communication design ability of undergraduate students. Bansomdejchaopraya Rajabhat University. Office of Academic Resources and Information Technology, คลังข้อมูลดิจิทัล สำนักวิทยบริการและเทคโนโลยีสารสนเทศ, accessed November 23, 2024, http://202.29.54.157/s/library/item/2890