Expanding the Approaches to User Experience
http://www.boxesandarrows.com/archives/expanding_the_approaches_to_user_experience.php

Olsen, George
Boxes and Arrows
2003

Abstract:

Jesse James Garrett’s 'The Elements of User Experience' diagram has become rightly famous as a clear and simple model for the sorts of things that user experience professionals do. But as a model of user experience it presents an incomplete picture with some serious omissions—omissions I’ll try address with a more holistic model.