MAKARCZUK, Anna Krystyna and KOWALEWSKI, Michał. Physical activity and body posture of younger school children in the opinion of parents. Journal of Education, Health and Sport. Online. 20 December 2020. Vol. 10, no. 12, pp. 138-150. [Accessed 3 July 2025]. DOI 10.12775/JEHS.2020.10.12.013.