Gloria Bordogna Paola Carrara Sergio Chiesa Stefano Spaccapietra A Dual Representation of Uncertain Dynamic Spatial Information. 652-659 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2715&spage=652 2003 conf/ifsa/2003 IFSA db/conf/ifsa/ifsa2003.html#BordognaCCS03