1. Bonnie RJ , Stratton K , Kwan LY , eds. Public health implications of raising the minimum age of legal access to tobacco products. Washington DC: National Academies Press US, 2015.
2. California Department of Public Health. New landmark California tobacco 21 law. 2016 https://www.cdph.ca.gov/programs/tobacco/Pages/Tobacco21.aspx (accessed 24 May 2017).
3. State of Hawaii. Department of Health, Tobacco Control – Chronic Disease Prevention & Health Promotion division. Retail sales. 2016 http://health.hawaii.gov/tobacco/home/retailx/ (accessed 24 May 2017).
4. Health Canada. Seizing the opportunity: the future of tobacco control in Canada. Ottawa, ON: Health Canada, 2017.
5. Chung-Hall J , Craig L , Driezen P , et al . Canadian smokers' support for tobacco endgame strategies: findings from the ITC Canada survey. Waterloo, Ontario: ITC Project, University of Waterloo, 2016.