1. Renewable energy policy and barriers;Beck,2004
2. World Bank Solar Home System projects: experiences and lessons learned 1993–2000;Cabraal,2000
3. GNESD (2006) Poverty Reduction: Can Renewable Energy make a real contribution?, Global Network on Energy for Sustainable Development. Retrieved: June 25, 2007, http://www.gnesd.org/Downloadables/PovertyReductionSPM.pdf.
4. A Comparison of Web and Mail Survey Response Rates;Kaplowitz;Public Opin. Q.,2004
5. World Bank/GEF Solar Home Systems Projects: Experience and Lessons Learned 1993–2000;Marinot;Renew. Sustain. Energy Rev.,2001