1. Apple's Siri. https://www.apple.com/ios/siri/. Apple's Siri. https://www.apple.com/ios/siri/.
2. Google's Google Now. http://www.google.com/landing/now/. Google's Google Now. http://www.google.com/landing/now/.
3. Microsoft's Cortana. http://www.windowsphone.com/en-us/features-8--1. Microsoft's Cortana. http://www.windowsphone.com/en-us/features-8--1.
4. Smartphone OS Market Share Q1 2014. http://www.idc.com/prodserv/smartphone-os-market-share.jsp. Smartphone OS Market Share Q1 2014. http://www.idc.com/prodserv/smartphone-os-market-share.jsp.
5. Google's Android Wear. www.android.com/wear/. Google's Android Wear. www.android.com/wear/.