1. American Lung Association (2010) Children and teens smoking statistics [document on the internet]. Available from: http://www.lungusa.org/stop-smoking/about-smoking/facts-figures/children-teens-and-tobacco.html . Accessed 5 July 2010
2. World Health Organization (2002) Smoking statistics [document on the internet]. Available from: http://www.wpro.who.int/media_centre/fact_sheets/fs_20020528.htm . Accessed 5 July 2010
3. Health Canada (2009) Canadian tobacco use monitoring survey (CTUMS) Annual results, 2009 [document on the internet]. Available from: http://www.hc-sc.gc.ca/hc-ps/tobac-tabac/research-recherche/stat/ctums-esutc_2009-eng.php . Accessed 5 July 2010
4. National Center for Chronic Disease Prevention and Health Promotion (2010) Trends in the prevalence of tobacco use, national YRBS: 1991–2009 [document on the internet]. Available from: http://www.cdc.gov/HealthyYouth/yrbs/pdf/us_tobacco_trend_yrbs.pdf . Accessed 5 July 2010
5. Office of National Statistics (2010) General lifestyle survey 2008: smoking and drinking among adults 2008 [document on the internet]. Available from: http://www.statistics.gov.uk/downloads/theme_compendia/GLF08/GLFSmoking&DrinkingAmongAdults2008.pdf . Accessed 5 July 2010