In: Robert F. Erbacher; Philip C. Chen; Jonathan C. Roberts; Matti T. Gröhn; Katy Börner (Hrsg.). Visualization and Data Analysis 2003. SPIE Conference on Visualization and Data Analysis, January 20-24, Santa Clara, Convention Center, CA, USA, Pages 268-278, Proceedings of the SPIE, Vol. 5009, No. 1, ISBN 0-8194-4809-5, SPIE, 2003.