1. C. Nedler , Market Outlook Part 2: Energy. Skyrocketing Fossil Fuel Prices Favor Renewables, Energy Capital Newsl., 2008, Energy and Capital, http://www.energyandcapital.com/articles/market-outlook-energy/655, (April, 2008)
2. J. L. Swain , Another Sunny Year for Solar Power, Vital Signs Online 2008, Worldwatch Institute, http://www.worldwatch.org/node/5449, September, 2008
3. Y. Zhao , Renewable Energy: China, Special Unit for South-South Cooperation V8, 2002, ch. 3, pp. 28–34, United Nations Development Programme,http://tcdc.undp.org/sie/experiences/vol8/China.pdf (August, 2008)
4. R. Wiser and G.Barbose, Renewables Portfolio Standards in the United States, 2008, pp. 12–20, Lawrence Berkeley National Laboratory,http://eetd.lbl.gov/ea/ems/reports/lbnl-154e.pdf (August, 2008)
5. C. Hammerle , 21st European Photovoltaic Solar Energy Conference, 2006, pp. 2631–2633