Марченко, С., and В. Голубов. “Peculiarities of Game Modes Effect on Dynamics of Speed Development in Boys of Primary School Age”. Teorìâ Ta Metodika Fìzičnogo Vihovannâ, no. 4, Dec. 2015, pp. 17-24, doi:https://doi.org/10.17309/tmfv.2015.4.1152.