@inproceedings{SabatoSh07,
 author = {Sabato, Sivan and Shalev-Shwartz, Shai},
 title = {Prediction by categorical features: generalization properties and application to feature ranking},
 booktitle = {Proceedings of the 20th annual conference on Learning theory (COLT)},
 year = {2007},
 pages = {559--573},
}