1. Gartner: Gartner says Worldwide Mobile Phone Sales Grew 17 Per Cent in First Quarter (2010)
2. International Telecommunication Union.: ITU sees 5 billion mobile subscriptions globally in 2010; Available from: http://www.itu.int/newsroom/press_releases/2010/06.html (2010)
3. BBC News Technology: Over 5 billion mobile phone connections worldwide.[cited 2010 3/11]; Available from: http://www.bbc.co.uk/news/10569081 (2010)
4. Tofel, K.C.: Android Sales Overtake iPhone in the U.S. [cited 2010 13/10]; Available from: http://gigaom.com/2010/08/02/android-sales-overtake-iphone-in-the-u-s/ (2010)
5. Apple Inc.: iOS4. [cited 2010 12/11]. Available from: http://www.apple.com/iphone/ios4/ (2010)