Boćkowski, R., J. Kotowska, A. Szylińska, A. Turoń-Skrzypińska, and I. Rotter. “The Influence of Physical Activity on the Mood of People Subjected to Standard Rehabilitation After Cardiac Surgery”. Journal of Education, Health and Sport, vol. 9, no. 1, Jan. 2019, pp. 263-72, https://apcz.umk.pl/JEHS/article/view/6535.