1. Sieminski A. International Energy Outlook 2013, U.S. Energy Information Administration; 2013.
2. Energy Information and Administration (EIA), 2013.
3. 〈http://www.nrel.gov〉.
4. 〈https://yearbook.enerdata.net/〉
5. National Power Sector Report, viewed 2 March 2014, and provided by Frank Haugwitz, Asia Europe Clean Energy (Solar) Advisory Co. Ltd. (AECEA), and personal communication with REN21, March 2014.