Rzepka, A., K. Radziszewski, K. Kędziora-Kornatowska, and M. Dzierżanowski. “Physical Activity As a Remedy for ‘cheerful’ Aging Which Prevents from Chronic Diseases”. Journal of Education, Health and Sport, vol. 6, no. 13, Dec. 2016, pp. 183-99, https://apcz.umk.pl/JEHS/article/view/4171.