Kielnar, R., and E. Domka-Jopek. “The importance of the evaluation of the quality of life before and after a three – month cardiological group rehabilitation of patients suffering from coronary heart disease”. European Journal of Clinical and Experimental Medicine, vol. 3, no. 4, Dec. 2005, pp. 355–361, https://journals.ur.edu.pl/ejcem/article/view/13440.