Designing Tip Windows
For the full GOMS model: Card, Stuart K., Moran, Thomas P., Newell, Alan. The Psychology of Human-Computer Interaction, Lawrence Erlbaum Associates, 1983.
For the useful keystroke level subset, plus many interesting and provocative ideas: Raskin, Jef. The Humane Interface, ACM Press, 2000.
Hugh Fisher (firstname.lastname@example.org) is a system administrator, 2-D/3-D interactive graphical programmer and part-time lecturer. He has strong opinions on the usability of Linux systems and hopes to inflict these on a wider audience by writing for Linux Journal.