1. Internet world stats. [Online]. Available: 〈http://www.internetworldstats.com/stats.htm〉.
2. Cisco white papers, Cisco Visual Networking Index: Forecast and Methodology, 2014–2019, 2015. [Online]. Available: 〈http://www.cisco.com/c/en/us/solutions/collateral/service-provider/ip-ngn-ip-next-generation-network/white_paper_c11-481360.html〉.
3. Trends in worldwide ICT electricity consumption from 2007 to 2012;Van Heddeghem;Comput. Commun.,2014
4. SMART 2020: Enabling the low carbon economy in the information age, 2008. [Online]. Available: 〈http://www.smart2020.org/_assets/files/02_smart2020Report.pdf〉.
5. ICT and CO2 emissions;Parliamentary office of science and technology;Postnote,2008