Ian E. Smith Giovanni Iachello Mika Raento Mobile HCI 2004 Workshop on Location Systems Privacy and Control. 525-526 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3160&spage=525 2004 conf/mhci/2004 Mobile HCI db/conf/mhci/mhci2004.html#SmithIR04