1. [1] Android.com. http://www.android.com/
2. [2] Open Handset Alliance. http://www.openhandsetalliance.com/
3. [3] The NPD Group, “The NPD group: Motorola, HTC drive Android to smartphone os lead in the U.S.” http://www.npd.com/press/releases/press_100804.html
4. [4] Android Market Statistics. http://www.androlib.com/appstats.aspx
5. [5] Android Developers, “Application licensing.” http://developer.android.com/guide/publishing/licensing.html