Janyce Wiebe Ellen Riloff Creating Subjective and Objective Sentence Classifiers from Unannotated Texts. 486-497 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3406&spage=486 2005 conf/cicling/2005 CICLing db/conf/cicling/cicling2005.html#WiebeR05