F. Suchanek, G. Kasneci, and G. Weikum. Proceedings of the 16th international conference on World Wide Web, page 697--706. New York, NY, USA, ACM, (2007)
W. Shen, J. Wang, P. Luo, and M. Wang. Proceedings of the 21st international conference on World Wide Web, page 449--458. New York, NY, USA, ACM, (2012)