@article{3:46,author={Ron Bekkerman and Ran El-Yaniv and Naftali Tishby and Yoad Winter}, Title={Distributional Word Clusters vs. Words for Text Categorization
(Kernel Machines Section)},journal={Journal of Machine Learning Research},volume={3}, url={http://www.jmlr.org/papers/volume3/bengio03a/bengio03a.pdf}}