The online promotion strategies of e cigarette and heated tobacco product retailers in South Korea following the COVID 19 pandemic: Implications for regulation Changes in E Cigarette Use Among U.S. Adults, 20192021 American Journal of Preventive Medicine Study Reveals Teens May Not be Aware of Nicotine Levels in E Cigarettes SBU News Beijing, China. 25th Sep, 2019. E cigarettes are sold in a grocery store in downtown Beijing on Wednesday, September 25, 2019. China, the world's largest tobacco market, may introduce regulations for the e cigarette Harvard scientist finds microbial contaminants in e cigs Harvard Gazette