6EHRING M, ERMAEDCHE A. ontology focused ling of Web documents[J].Proeeedings of the 2003ACM Sympos iumon Applied ComPuting,2003,1(3):624-626.
7CUTLER M, SHIH Y, MENG W. Using the structure of HTML documents to improve retrieval [A]. Proceedings of the USENIX Symposium on Interuet Technologies and Systems Monterey [C]. California: California Press, 1997:241- 251.
8Mdiligenti F C. Focused crawling using context graphs[A]. Proceedings of the 26th International Conference on Very Large Data Bases[C]. Cairo : Cairo Press, 2000 : 527-534.