https://pubchem.ncbi.nlm.nih.gov/compound/89594

Chemistry and pharmacology of nicotine.

https://www.drugabuse.gov/drugs-abuse/tobacconicotine-e-cigs

National Institute on Drug Abuse site for tobacco addiction.

https://betobaccofree.hhs.gov/health-effects/nicotine-health/index.html

U.S. Department of Health & Human Services website on the effects of smoking on health.

http://www.dnalc.org/view/955-Causes-Smoking-Tobacco-history.html

Slideshow on the history of tobacco.

http://www.dnalc.org/view/961-Causes-Smoking-Nicotine-connection.html

Presentation on smoking and cancer, with audio and animations.

https://www.youtube.com/watch?v=yoOLVM1U5L8

Video about nicotine in the brain.

https://pubchem.ncbi.nlm.nih.gov/compound/2519

Chemistry and pharmacology of caffeine.

http://www.webmd.com/balance/caffeine-myths-and-facts

Basic information on caffeine.

http://www.cspinet.org/new/cafchart.htm

Caffeine content of food and drugs.