1. Future Energy: Improved, Sustainable and Clean Options for Our Planet;International Union of Pure and Applied Chemistry,2008
2. The Future of Oil and Gas Fossil Fuels in Future Energy: Improved, Sustainable and Clean Options for Our Planet, for the International Union of Pure and Applied Chemistry;Goodwin,2008
3. Dictionary of Energy;Cleveland,2009
4. (accessed 29.07.13).
5. (accessed 29.07.13).