Warnill Chung Hae-Young Bae A Specification of a Moving Objects Query Language over GML for Location-Based Services. 788-793 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3007&spage=788 2004 conf/apweb/2004 APWeb db/conf/apweb/apweb2004.html#ChungB04