Zelenskiy K.G., Ponomarev G.N., Kostyuchenko V.F., and Zverev V.D. “The Performance Indicators of Elite Athletes Aged 15-16 in Sports-Related Activities”. Theory and Practice of Physical Culture, no. 3, May 2025, pp. 19-22, http://tpfk.ru/index.php/TPPC/article/view/1283.