Hans Gellersen Kjeld Schmidt Michel Beaudouin-Lafon Wendy E. Mackay Proceedings of the Ninth European Conference on Computer Supported Cooperative Work, 18-22 September 2005, Paris, France ECSCW Springer 2005 db/conf/ecscw/ecscw2005.html 1-4020-4022-9 1-4020-4023-7