1. Institute for Global Tobacco Control . Country laws regulating e-cigarettes: a policy scan Johns Hopkins Bloomberg school of public health, 2020. Available: https://www.globaltobaccocontrol.org/e-cigarette_policyscan [Accessed 8 July 2020].
2. Electronic cigarettes: a brief update;Mathur;J R Coll Physicians Edinb,2018
3. Should we recommend e-cigarettes to help smokers quit?
4. National Institute for Health and Care Excellence . Stop smoking interventions and services. NICE guideline [NG92], 2018. Available: https://www.nice.org.uk/guidance/ng92/chapter/recommendations#advice-on-ecigarettes [Accessed 16 July 2019].
5. NHS Health Scotland . E-Cigarettes consensus statement, 2017. Available: http://www.healthscotland.scot/publications/e-cigarettes-consensus-statement [Accessed 16 Aug 2019].