B. Navarro Bullock, H. Lerch, A. Roßnagel, A. Hotho, und G. Stumme. Proceedings of the 11th International Conference on Knowledge Management and Knowledge Technologies, Seite 15:1--15:8. New York, NY, USA, ACM, (2011)
F. Benevenuto, T. Rodrigues, V. Almeida, J. Almeida, und M. Goncalves. Proceedings of the 32nd international ACM SIGIR conference on Research and development in information retrieval, Seite 620--627. New York, NY, USA, ACM, (2009)
J. van Wamelen, und D. de Kool. Proceedings of the 2nd International Conference on Theory and Practice of Electronic Governance, Seite 349--354. Cairo, Egypt, ACM, (2008)