N. Kern, and B. Schiele. Location- and Context-Awareness, Second International Workshop (LoCA'06), volume 3987 of LNCS, page 134-150. Berlin Heidelberg, Germany, Springer, (10-11 May 2006)
S. Davis, and C. Gutwin. GI '05: Proceedings of the 2005 conference on Graphics interface, page 145--152. School of Computer Science, University of Waterloo, Waterloo, Ontario, Canada, Canadian Human-Computer Communications Society, (2005)