1. World Health Organization. WHO report on the global tobacco epidemic, 2009: implementing smoke-free environments. 2009. http://www.who.int/tobacco/mpower/2009/en/ .
2. U.S. Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta, GA; 2006. https://www.ncbi.nlm.nih.gov/books/NBK44324/ . Accessed 2 Jan 2017.
3. Twardella D, Bolte G, Fromme H, Wildner M, von Kries R, GME Study Group. Exposure to secondhand tobacco smoke and child behaviour - results from a cross-sectional study among preschool children in Bavaria. Acta Paediatr. 2010;99(1):106–11. http://onlinelibrary.wiley.com/doi/10.1111/j.1651-2227.2009.01522.x/abstract .
4. Stiby AI, Macleod J, Hickman M, Yip VL, Timpson NJ, Munafò MR. Association of maternal smoking with child cotinine levels. Nicotine Tob Res. 2013;15(12):2029–36.
5. U.S. Department of Health and Human Services. Maternal, infant, and child health. 2020 topics and objectives. 2014;15 SRC-. https://www.healthypeople.gov/2020/topics-objectives/topic/maternal-infant-and-child-health?topicid=26 . Accessed 2 Jan 2017.