1. Understanding the role of energy consumption in human development through the use of saturation phenomena;Martínez;Energy Policy,2008
2. United Nations, Human Development Report Office http://hdr.undp.org/en/statistics/hdi/ 2011
3. International Energy Outlook 2011
4. Key World Energy Statistics 2011
5. U.S. Energy Information Administration http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm 2011