Allison Temourian's paper published on reasons why dual users may use e-cigarettes and how this relates to both combustible cigarette and e-cigarette consumption.
https://doi.org/10.1016/j.pmedr.2022.101924
Temourian, A.A., Song, A.V., Halliday, D.M., Gonzalez, M., & Epperson, A.E. (...