- Journal of Intelligent Information Systems 36(2):167-195 (April 2011)
- World Wide Web 14(5-6):651-669 (October 2011)
- Wiley, Chichester, UK, (2003)
- O'Reilly, Beijing, 1. edition, (2002)
- Hanser, München, (2008)
- Springer, Berlin, (2003)
- Computer 42(5):90-94 (2009)
- O'Reilly, Sebastopol, CA, (2002)
- Personal and Ubiquitous Computing 13(4):255-264 (2009)
- Informatik-Spektrum 30(4):240-250 (2007)
- New Riders, Indianapolis, IN, (2002)
- Springer, Berlin, (2006)


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