Text: Preece, Rogers & Sharp
First edition: Ch 3, pp. 92 - 94
Second edition: Ch 3 pp. 116 - 118
McDaniel, S (2003) What's Your Idea of a Mental Model? Boxes and Arrows Viewed 28 February, 2007 <http://www.boxesandarrows.com/view/whats_your_idea_of_a_mental_model_ >