Martin Strohbach Hans-Werner Gellersen Gerd Kortuem Christian Kray Cooperative Artefacts: Assessing Real World Situations with Embedded Technology. 250-267 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3205&spage=250 2004 conf/huc/2004 Ubicomp db/conf/huc/ubicomp2004.html#StrohbachGKK04