Fanglap, S., and N. Intanam. “An Action Reserch on Development of Learning Achievement in Valleyball Course by Using STAD Cooperative Learning Method for Prathom Suksa 6 Students in Bannonglai (Putpermwattanarat) School under Ubon Ratchathani Primary Educational Service Area Office 1”. Ubon Ratchathani Journal of Research and Evaluation, vol. 6, no. 1, Aug. 2021, pp. 59-68, https://so06.tci-thaijo.org/index.php/ubonreseva/article/view/251034.