T. Sakaki, M. Okazaki, and Y. Matsuo. Proceedings of the 19th International Conference on World Wide Web, page 851--860. New York, NY, USA, ACM, (2010)
B. Bullock, H. Lerch, A. Roßnagel, A. Hotho, and G. Stumme. Proceedings of the 11th International Conference on Knowledge Management and Knowledge Technologies, page 15:1--15:8. New York, NY, USA, ACM, (2011)