PHASOMBUN, Nutnaphang, Tanida JULVANICHPONG, and Warakorn SUPWIRAPAKORN. 2014. “AN EFFECT OF GESTALT GROUP COUNSELING ON SELF-EFFICACY AND BADMINTON SERVING”. Journal of Sports Science and Technology 14 (1):249-57. https://he01.tci-thaijo.org/index.php/JSST/article/view/44107.