“THE EFFECT OF DRILL VARIATIONS TRAINING ON THE OVERHAND SERVE DEFENSE ABILITY IN VOLLEYBALL AT SMA HANG TUAH 1 SURABAYA” (2025) Journal Sports Exercise Science International (SESI), 1(1), pp. 60–63. Available at: https://sesi.karirpublisher.org/index.php/sesi/article/view/19 (Accessed: 22 February 2026).