Marpaung, A.F.S., Sudradjat Wiradihardja and Kurnia Tahki 2021. THE EFFECT OF ANXIETY, CONFIDENCE, AND MOTIVATION ON THE PERFORMANCE OF NATIONAL VOLLEYBALL REFEREE PROVINCE OF NORTH SUMATRA. Gladi : Jurnal Ilmu Keolahragaan. 12, 05 (Dec. 2021), 403 - 411. DOI:https://doi.org/10.21009/GJIK.125.07.