Puteri, Saskia Oktaviani, et al. “Relationship Between Age, Exercise Habits, Cigarette Smoke Duration Exposure, and Lung Vital Capacity in Passive Smokers”. Majalah Kedokteran Bandung, vol. 55, no. 2, June 2023, pp. 65-69, doi:10.15395/mkb.v55n2.2169.