1. The lost civilizations of the Stone Age;Rudgley,1999
2. http://www.poppies.ws/poppies/opium-effects.html
3. http://opioids.com/timeline/
4. The Ebers papyrus: a new English translation, commentaries and glossaries;Ghalioungui,1987
5. http://en.wikipedia.org/wiki/Pedanius_Dioscorides