1. International Energy Annual 2001;;Energy Information Administration,2003
2. Oil crises and climate challenges—30 years of energy use in IEA countries;;International Energy Agency,2004
3. Electricity information—Part II. USA;;International Energy Agency,2001
4. Communication from the commission energy for the future: renewable sources of energy.;European Commission,1997
5. Green paper towards a European strategy for the security of energy supply;;European Commission,2001