1. BP Statistical Report of World Energy, June 2017https://www.bp.com/content/dam/bp/en/corporate/pdf/energy-economics/statistical-review-2017/bp-statistical-review-of-world-energy-2017-full-report.pdf
2. https://data.worldbank.org/indicator/EG.USE.COMM.FO.ZS
3. Global Trends in Renewable Energy Investments,2017
4. WilderHill New Energy Global Innovation Indexhttp://www.nexindex.com/
5. Solar Energy Markets—An Analysis of the Global Solar Industry;Jordan,2013