1. Electric Power Generation
2. REN21 2014 The First Decade (2004-2014), 10 Years of Renewable Energy Progress http://www.ren21.netPortals/0/documents/activities/Topical%20Reports/REN21_10yr.pdf
3. Wikipedia, Wind power. [Online] https://en.wikipedia.org/wiki/Wind_power#cite_note-GWEC_Market-1
4. IEA PVPS International Energy Agency Photovoltaic Power Systems Programme 2015 IEA PVPS Report: 2014 Snapshot of Global PV Markets http://www.iea-pvps.org/fileadmin/dam/public/report/technical/PVPS_report_-_A_Snapshot_of_Global_PV_-_1992-2014.pdf