I.N. Medvedev, O.A. Razzhivin, A.V. Dorontsev, and V.V. Belyaev. “Functional Features of the Heart in Cyclists”. Theory and Practice of Physical Culture, no. 4 (April 27, 2023): 46–48. Accessed February 2, 2025. http://tpf1610220.nichost.ru/index.php/TPPC/article/view/570.