(Jaruwan Sonpang) จ. ส., and (Jensamut Sangpan) เ. แ. “TEACHER ROLES FOR SUPPORTING STUDENTS’ GEOMETRIC PROBLEM - SOLVING ABILITIES IN CLASSROOM TAUGHT THROUGH OPEN APPROACH”. Journal of Education and Innovation, vol. 19, no. 4, Jan. 2018, pp. 65-77, https://so06.tci-thaijo.org/index.php/edujournal_nu/article/view/108400.