E cigarettes vs. Traditional Cigarettes: What are the Health Risks? The Sparman Clinic E Cigarettes, Vapes, and other Electronic Nicotine Delivery Systems (ENDS) FDA Health effects and known pathology associated with the use of E cigarettes ScienceDirect E cigarettes should be offered to smokers, say doctors BBC News Vaping vs smoking: nicotine equivalents explained Nicotine absorption from electronic cigarette use: comparison between first and new generation devices Scientific Reports