Lupo, C., L. Capranica, C. Cortis, and A. Tessitore. “Competitive Training Load: Could It Be Excessive in Pre- Adolescent Taekwondo Athletes?”. Italian Journal of Anatomy and Embryology, vol. 119, no. 1, Mar. 2015, p. 114, https://oajournals.fupress.net/index.php/ijae/article/view/2467.