M. Prilla. Proceedings of 11th International Conference on Business Information
Systems, BIS 2008, Innsbruck, Austria, page 130-141. Innsbruck, Austria, (2008)
B. Sigurbjörnsson, and R. van Zwol. WWW '08: Proceeding of the 17th international conference on World
Wide Web, page 327--336. New York, NY, USA, ACM, (2008)