García, José, V. De Lera, D. Lacambra, F. Gimeno, and Álvaro Alesanco. “Design and Development of an Android App Based on Firebase in the Study of Unsportsmanlike Behaviors in Grassroots Tennis Competitions”. Journal of Mobile Multimedia 17, no. 4 (June 21, 2021): 603–636. Accessed April 20, 2024. https://journals.riverpublishers.com/index.php/JMM/article/view/5561.