Chudzik, R., K. Jarosz-Chudzik, M. Gołębiowska, B. Gołębiowska, and M. Kulczyński. “New Possibilities in Pectus Excavatum”. Journal of Education, Health and Sport, vol. 8, no. 7, July 2018, pp. 562-8, https://apcz.umk.pl/JEHS/article/view/5802.