Duda, Anna, and Ewa Klimek-Piskorz. “Assessment of Changes in the Physical Fitness and Capacity of Juniors Playing Football Non-Professionally in the 2022 23 Season”. Państwo I Społeczeństwo State and Society, vol. 24, no. 2, Dec. 2024, pp. 123-3, doi:10.48269/2451-0858-pis-2024-2-009.