1. Alexa.com http://www.alexa.com/topsites , 16 juillet 2013, « Top 500 Global Sites », url : <>
2. Anderson Free: The future of a radical price Chris, 2009, Random House, New York.
3. Why do commercial companies contribute to open source software?;Andersen-Gott Morten;International Journal of Information Management,2012
4. The Hi-Tech Gift Economy;Barbrook Richard;First Monday,1998
5. Battelle The Search John, 2005, Nicholas Brealey, Londres.