https://en.wikipedia.org/wiki/Effects_of_electronic_cigarettes_on_human_brain_development

cotinine

https://pubmed.ncbi.nlm.nih.gov/32205338/

Several studies have demonstrated that experienced e-cigarette users achieve levels of cotinine similar to cigarette smokers.

https://pubmed.ncbi.nlm.nih.gov/32383409/

https://pubmed.ncbi.nlm.nih.gov/30985285/

https://www.researchprotocols.org/2019/4/e12304/

https://www.researchprotocols.org/2019/4/e12304/#Copyright

E-Cigarettes and Cancer Risk

PMID: 31619443 DOI: 10.1158/1940-6207.CAPR-19-0346

Nicotine Toxicity: Protecting Children From E-Cigarette Exposure

PMID: 31855987 DOI: 10.1097/01.NURSE.0000615084.47597.14

https://pubmed.ncbi.nlm.nih.gov/32179055

https://pubmed.ncbi.nlm.nih.gov/32301069

http://www.euro.who.int/__data/assets/pdf_file/0008/443663/Heated-tobacco-products-brief-eng.pdf?ua=1