B. Weischedel, and E. Huizingh. ICEC '06: Proceedings of the 8th international conference on Electronic commerce, page 463--470. New York, NY, USA, ACM, (2006)
M. Morris, and E. Horvitz. UIST '07: Proceedings of the 20th annual ACM symposium on User interface software and technology, page 3--12. New York, NY, USA, ACM, (2007)
C. Hänger, and C. Krätzsch. Wissenschaftskommunikation der Zukunft 4. Konferenz der Zentralbibliothek, volume 18 of Schriften des Forschungszentrums Jülich, Reihe Bibliothek / Library, (2007)