Bartczak, Maria, and Elżbieta Balcerzyk-Barzdo. “Willingness to Perform Bystander CPR before and After the BLS AED Course”. Polish Journal of Public Health, vol. 121, no. 3, Sept. 2011, pp. 234-7, https://czasopisma.umlub.pl/pjph/article/view/1986.