1. International Energy Outlook 2009, Energy Information Administration, Department of Energy, Washingston, DC, 2009
2. J. Holdren , Robert C. Barnard Environmental Lecture at American Association for the Advancement of Science, Washington, DC, 2007
3. N. Lewis , California Institute of Technology, http://nsl.caltech.edu/files/energy6.pdf
4. Powering the planet: Chemical challenges in solar energy utilization