1. United Nations, Department of Economic and Social Affairs, Population Division (2017) World population prospects: the 2017 revision, key findings and advance https://esa.un.org/unpd/wpp/Publications/Files/WPP2017_KeyFindings.pdf
2. International energy agency (2016) World energy outlook https://www.iea.org/media/publications/weo/WEO2016Chapter1.pdf
3. BP Statistical Review of World Energy (2016) BP energy outlook https://www.bp.com/content/dam/bp/pdf/energy-economics/statistical-review-2016/bp-statistical-review-of-world-energy-2016-full-report.pdf
4. Linden D, Reddy TB (2002) Handbook of batteries. McGraw-Hill New York, Vol. 3rd ed
5. Winter M, Brodd RJ (2004) What are batteries, fuel cells, and supercapacitors? Chem Rev 104(10):4245–4270. https://doi.org/10.1021/cr020730k