Aprilo, Ians, Poppy Elisano Arfanda, M. Adam Mappaompo, Hasbi Asyhari, M. Imran Hasanuddin, and Muhammad Isnawan Syafir. “Development of Tennis Spin Serve Technique Observation Instrument: The Quality Tennis Learning in Higher Education”. ETDC: Indonesian Journal of Research and Educational Review 4, no. 3 (June 2, 2025): 509–516. Accessed July 30, 2025. https://etdci.org/journal/ijrer/article/view/3020.