Wójtowicz-Chomicz, Katarzyna, and Andrzej Borzęcki. “Problem of Nicotine Addiction and Passive Smoking Among Students of Medical University of Lublin”. Polish Journal of Public Health, vol. 119, no. 1, Jan. 2009, pp. 64-67, https://czasopisma.umlub.pl/pjph/article/view/2196.