The Eyes Have It A Research Paper by Ben Shneiderman www.cs.umd.edu The Visual Information Seeking Mantra visualizationinformationdata
Readings in Information Visualization: Using Vision to Think A Book by Ben Shneiderman visualizationthinkinginformation
The case against heatmaps An Article by Oliver Palmer www.oliverpalmer.com Visualised aggregations of click activity are a low effort, low signal waste of time and best avoided in favour of actual research. uxmetrics