SIRMAN, Y., PREYS , N. and SAVYTSKYI, I. Results of construction of correlation fields with trend lines and determination of direction of relationships between studied indicators. Journal of Education, Health and Sport. Online. 30 June 2021. Vol. 11, no. 6, pp. 348-361. [Accessed 25 December 2025]. DOI 10.12775/JEHS.2021.11.06.037.