Willwéber, Tomas, and Ivan Čillík. “Physical Development and General Physical Performance of Children at the Age of 5 – 10 Years”. Journal of Education, Health and Sport 7, no. 8 (August 24, 2017): 309–316. Accessed July 27, 2024. https://apcz.umk.pl/JEHS/article/view/4733.