L. Wu, M. Li, Z. Li, W. Ma, and N. Yu. MIR '07: Proceedings of the international workshop on Workshop on multimedia information retrieval, page 115--124. New York, NY, USA, ACM, (2007)
J. Wang, A. De Vries, and M. Reinders. Proceedings of the 29th annual international ACM SIGIR conference on Research and development in information retrieval, page 501--508. ACM, (2006)