Soemardiawan, Soemardiawan, Mujriah Mujriah, Intan Primayanti, and Lalu Heri Darmawan. 2024. “Improving Learning Outcomes of the Upper Serve Using Problem-Based Introduction (PBI) Learning in Volleyball Games”. Indonesian Journal of Sport Management 4 (3). https://doi.org/10.31949/ijsm.v4i3.11114.