Halverson, Christine A.; Julia, Luc E.; Cheyer, Adam J. (2000): Working through Walls: Mediating Cooperation in Dynamic Spaces. COOP 2000: Cooperative Systems Design - The Use of Theories and Models. IOS Press. ISBN: 1-58603-042-6. pp. 66-80. Mobility. Sophia-Antipolis, February. 23-26 May 2000