1. Huber, P., Mills, M.P.: Dig more coal—the PCs are coming. Forbes, pp. 70–72 (1999). http://www.forbes.com/forbes/1999/0531/6311070a.html . Accessed 10 August 2014
2. Koomey, J.G.: Rebuttal to testimony on ’Kyoto and the internet: the energy implications of the digital economy’. Lawrence Berkeley National Laboratory (2000). Accessed from: http://enduse.lbl.gov/Info/annotatedmillstestimony.pdf
3. Roth, K., Goldstein, F. Kleinman, J.: Energy Consumption by Office and Telecommunications Equipment in Commercial Buildings-Volume I: Energy Consumption Baseline. Washington, DC: Prepared by Arthur D. Little for the U.S. Department of Energy. A.D. Little Reference no. 72895 00. http://www.biblioite.ethz.ch/downloads/Roth_ADL_1.pdf (January 2002)
4. OGasawara, A.: Energy Issues Confronting the Information and Communications Society-Need to reduce the power Consumed by the Communications Infrastructure. Science and Technology Trends. Quarterly Review, 21. http://www.nistep.go.jp/achiev/ftx/eng/stfc/stt021e/qr21pdf/STTqr2102.pdf (October 2006)
5. Koomey, J.: Growth in data center electricity use 2005 to 2010. A report by Analytical Press, completed at the request of The New York Times. http://www.missioncriticalmagazine.com/ext/resources/MC/Home/Files/PDFs/Koomey_Data_Center.pdf (2011) Accessed 25th June, 2014