Handheld Devices and the Flow of Functionality
http://www.sprez.com/articles/handheld-user-interface-flow.html

Ferlazzo, Ellen Lawson
Sprezzatura Systems
2002

Abstract:

Handheld devices and small appliances pose a unique challenge to the interface designer. The blur between user interface and functionality (interface vs. interaction) is even more pronounced in these environments. The interface of any small device is extremely important; yet, more than ever, the necessity to build in exactly (and only) what is required by the user is extremely important!