Himawan, Ahmad, et al. “Comparison of Service Technique Effectiveness (Volley Serve Vs. Drop Serve) and Its Contribution to First Point Win Percentage in Amateur Pickleball”. Journal of Racket Sports Performance & Science (JRSPS), vol. 1, no. 1, Nov. 2025, pp. 30-35, https://journal.unesa.ac.id/index.php/jrsps/article/view/47222.