Widiyanto W, Setyawan H, Suharjana S, Purwanto S, Indra EN, Prayudho S, et al. Article RETRACTED due to manipulation by the authors Los diferentes resultados en lsa habilidades de servicio de los tenistas jóvenes evaluadas según el género y la edad (The Differences Result in Serve Skill of Junior Tennis Players Assessed Based on Gender and Age): Article RETRACTED due to manipulation by the authors. Retos [Internet]. 2024 May 1 [cited 2026 Jun. 10];54:272-8. Available from: https://www.revistaretos.org/index.php/retos/article/view/102757