P. Dolog, N. Henze, W. Nejdl, and M. Sintek. Proceedings of the 13th international World Wide Web conference on Alternate track papers & posters, page 170--179. New York, NY, USA, ACM, (2004)
Y. LeCun, F. Huang, and L. Bottou. Computer Vision and Pattern Recognition, 2004. CVPR 2004. Proceedings
of the 2004 IEEE Computer Society Conference on, 2, page II-97--104 Vol.2. (2004)