@inproceedings{KimEtal07,
 author = {Jongwan Kim and Dejing Dou and Haishan Liu and Donghwi Kwak},
 title = {Constructing A User Preference Ontology for
Anti-spam Mail Systems.},
 booktitle = {Proceedings of the 20th
Canadian Conference on Artificial Intelligence (Canadian AI)},
 pages = {272-283},
 year = {2007},
 }