Jesús Ibáñez Antonio F. Gómez-Skarmeta Josep Blat Querying Virtual Worlds. A Fuzzy Approach. 59-68 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2972&spage=59 2004 conf/micai/2004 MICAI db/conf/micai/micai2004.html#IbanezGB04