http://www.aspirin-foundation.com/history-of-aspirin/the-chemistry-of-aspirin/
http://www.chem.latech.edu/~deddy/chem104/104Aspirin.htm
http://chemistry.about.com/od/moleculescompounds/a/caffeine.htm
http://www.livescience.com/41999-antihistamines-drowsy-benadryl-allergies.html