1. International Energy Outlook 2016 with Projections to 2040. A report by U.S. Energy Information Administration (EIA), 2016. https://www.eia.gov/outlooks/ieo/pdf/0484(2016).pdf) [Accessed: Dec 15, 2017]
2. International Energy Outlook 2017 with Projections to 2040. A report by U.S. Energy Information Administration (EIA), 2017. https://www.eia.gov/outlooks/ieo/pdf/0484(2017).pdf [Accessed: Feb 05, 2018]
3. Key World Energy Trends, Excerpt from World Energy Balance (2016), A Report by International Energy Agency (IEA); 2016
4. Key world energy statistics, A report by International Energy Agency (IEA). 2017. https://www.iea.org/publications/freepublications/publication/KeyWorld2017.pdf [Accessed: Jan 05, 2017]
5. BP Statistical Review of World Energy June 2017. https://www.bp.com/content/dam/bp/en/corporate/pdf/energy-economics/statistical-review-2017/bp-statistical-review-of-world-energy-2017-full-report.pdf [Accessed: Feb 15, 2018]