Шварц, А., П. Ліпіньська, and Б. Доланьські. “Method of Evaluation of Special Physical Fitness of Fourteen-Year-Old Football Players”. Slobozhanskyi Herald of Science and Sport, no. 1, Apr. 2011, pp. 38-42, https://journals.uran.ua/index.php/1991-0177/article/view/35523.