Ziv Bar-Yossef Yaron Kanza Yakov A. Kogan Werner Nutt Yehoshua Sagiv Querying Semantically Tagged Documents on the World-Wide Web. 2-19 http://link.springer.de/link/service/series/0558/bibs/1649/16490002.htm 1999 conf/ngits/1999 NGITS db/conf/ngits/ngits99.html#Bar-YossefKKNS99