Skotnikova A.V., Aleksandrova V.A., Serikova Yu.N., and Ovchinnikov V.I. “Normative Scales for Assessing Static Equilibrium in Junior Schoolchildren”. Theory and Practice of Physical Culture, no. 8, Nov. 2024, pp. 59-61, http://tpfk.ru/index.php/TPPC/article/view/1101.