2Definition of Information Extraction from http://en.wikipedia.org/wiki/Information_extraction.
3Berry,M.W.,Dumas,S.T.,&Letcher,T.A.(1995).Computational methods for intelligent information access.in Proceedings of Supercomputing'95,San Diego,CA,December 1995.Retrieved February 12,2006.from http://eiteseer.ist.psu.edu/berry95computational.html.
4Chen,J.,Yu,P.,and Ge,H.(2006).UNT 2005 TREC QA Participation: Using Lemur as IR Search Engine.Online Proceedings of the Fourteenth Text REtrieval Conference(TREC 2005).Available at:http://tree.nist.gov/pubs/ trec14/papers/unonh-texas.qa.pdf.
