Wiatrak, Adrian, Hanna Mosiejczuk, Aleksandra Szylińska, Aleksandra Rył, Agnieszka Turoń-Skrzypińska, Agata Maziarz, and Iwona Rotter. 2018. “The Effect of Smoking and Physical Activity Level on Exercise Capacity in Older Adults”. Journal of Education, Health and Sport 8 (11):240-52. https://apcz.umk.pl/JEHS/article/view/6288.