Ulenberg, G., A. Ulenberg, A. Grabowska-Gaweł, Łukasz Czapiewski, and M. Dąbrowska. “Postoperative Care in Geriatrics”. Journal of Education, Health and Sport, vol. 7, no. 8, Aug. 2017, pp. 1228-40, https://apcz.umk.pl/JEHS/article/view/5012.