Sources:
- http://about.zappos.com/
- http://www.deliveringhappiness.com/
- http://www.zappos.com/zappos-apps
- http://techcrunch.com/2013/05/20/zappos-rolls-out-ios-app-update-as-it-ponders-the-future-of-the-mobile-shopping-experience/
- http://about.zappos.com/meet-our-monkeys/tony-hsieh-ceo
- http://www.youtube.com/watch?v=5CcLIPaUz3E