1. WHO, Global Health Observatory (GHO) Datahttp://www.who.int/gho/phe/secondhand_smoke/en/
2. Law for the Promotion of Nation’s Health Enforcement Ordinance Article 6http://www.law.go.kr/lsInfoP.do?lsiSeq= 149119#AJAX
3. Guidelines on Protection from Exposure to Tobacco Smokehttp://www.who.int/fctc/cop/art%208%20guidelines_english.pdf?ua=1
4. The Census on Establishmentshttp://kosis.kr/ups/ups_01List.jsp
5. Characteristics of Social Smoking Among College Students