Sin, Tjung Hauw, and Budi Indra Ruslin. “Optimization of Achievement Motivation to Improve Long Jump Performance”. COUNS-EDU: The International Journal of Counseling and Education 3, no. 1 (May 23, 2018): 34–40. Accessed November 4, 2025. https://counsedu.iicet.org/index.php/counsedu/article/view/138.