Open Source GIS: A GRASS GIS Approach

Beginning MapServer: Open Source GIS Development (Expert's Voice in Open Sou...

Permutation Methods: A Distance Function Approach (Springer Series in...

Open Source GIS: A GRASS GIS Approach (The Springer International Series in Eng

GIS: A Visual Approach, Davis, Bruce

Beginning Mapserver: Open Source GIS Development by Kropla, Bill

Open Source GIS: A GRASS GIS Approach by Markus Neteler: Used