Here some Literature about Eye-Tracking:
- Duchowski, Eye Tracking Methodology: Theory and Practice, Springer
2007 (This explains the technical and scientifical approach behind the eye-tracking method in it's full scope. There's even a description of how to build your own linux interface to a tracking device)
- Nielsen/Pernice, Eyetracking Web Usability, New Riders 2010 (This shows the approach and results of a large scaled usability study performed with the eye-tracking method)
- Yarbus, Eye movements and vision, 1967 (This is the "root" literature about eye movement measurement itself, i.e. the very famous and often used picture The Visitor is cited from this book)
There is a lot more, but it's very specific on a theme (like perception in marketing etc.pp.), so I didn't mention it.
Also there are online ressources of eye-tracking studies that are very specific, but might also help i.e. about forms:
http://www.uxmatters.com/mt/archives/2006/07/label-placement-in-forms.php
http://www.cxpartners.co.uk/cxblog/web_forms_design_guidelines_an_eyetracking_study/