Published on in Vol 23, No 6 (2021): June
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/24435, first published
.
1 Center for Tobacco Control Research and Education, University of California, San Francisco, San Francisco, CA, United States
2 School of Information, University of Michigan, Ann Arbor, MI, United States
3 Department of Mathematics, University of California, Davis, Davis, CA, United States