RT Journal Article SR Electronic T1 Bringing attention to e-cigarette pH as an important element for research and regulation JF Tobacco Control JO Tob Control FD BMJ Publishing Group Ltd SP 413 OP 414 DO 10.1136/tobaccocontrol-2014-051540 VO 24 IS 4 A1 Stepanov, Irina A1 Fujioka, Naomi YR 2015 UL http://tobaccocontrol.bmj.com/content/24/4/413.abstract AB