1. IPCC Fourth Assessment Report, November, 2007.
2. World Population Prospects, 2006 Revision (UN).
3. Energy Balances of OECD Countries and Energy Balances of Non-OECD Countries 2005–2006.
4. OECD/IEA, World Energy Outlook, 2006.
5. IIASA, Global Energy Perspectives.