1. Shanidar IV, a Neanderthal Flower Burial in Northern Iraq
2. http://en.wikipedia.org/wiki/Flower#Usage.
3. Opium Poppy: Botany, Chemistry, and Pharmacology;Kapoor,1995
4. Fentanyl is a powerful opioid analgesic with a potency approximately 81 times that of morphine. It has been invented and first synthesized by Dr Paul Janssen, the founder of Janssen Pharmaceutica in 1959.
5. Janssen, P. A. J.; Gardocki, J. F. U.S. Patent 3141823, 1964.