6Hearst, M. A. Cat-a-Cone:An interactive interface for specifying searches and viewing retrieval results using a large category hierarchy. Proceedings of the Twentieth Annual International ACM SIGIR Conference, Philadelphia, PA, July 1997.
7Fensel, Dieter etc. Ontobroker in a Nutshell. ECDL 1998:663-664.
8Schatz, Bruce R. Information retrieval in digital libraries:bring search to the Net. Science, 1997, 275 (5298) : 327-334.
9Milstead, Jessica. Use of thesauri in the full-text environment.34th Clinic on Library Applications of Data Processing, Cochrane & Johnson, 1998.
10Khan, Latifur R. Ontology-based information selection, doctorate dissertation, University of Southern California, 2000.
