SAMEK, Ilona, JAŃCZYK, Magdalena and MILANOWSKA, Joanna. Physical activity of the society. Journal of Education, Health and Sport. Online. 24 September 2021. Vol. 11, no. 9, pp. 504-511. [Accessed 17 July 2024]. DOI 10.12775/JEHS.2021.11.09.065.