GRASS - Geographic Resources Analysis Support System

See GRASS Documentation project (Books and tutorials). Major parts of this tutorial have been translated and updated from the book:

Neteler, M. (2000): GRASS-Handbuch. Der praktische Leitfaden zum Geographischen Informationssystem GRASS. Geosynthesis 11, Geographisches Institut der Universitšt Hannover, 247 S. ISBN 3-927053-30-9 (A GRASS beginners tutorial in German language)

Search with CiteSeer (published GRASS papers).