Published on in Vol 20, No 6 (2018): June
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/9461, first published
.
1 RTI International, Research Triangle Park, NC, United States
2 US Food and Drug Administration, Center for Tobacco Products, Silver Spring, MD, United States
3 Battelle Memorial Institute, Aberdeen, MD, United States