Harikrishna Vasanta Yiu Shing Terry Tin Colin Boyd Mark Looi Juan Manuel González Nieto A Secure Framework for User Privacy in Heterogeneous Location Networks. 264-274 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3284&spage=264 2004 conf/mata/2004 MATA db/conf/mata/mata2004.html#VasantaTBLN04