Beatriz Sousa Santos Thomas Ertl Kenneth I. Joy 8th Joint Eurographics - IEEE VGTC Symposium on Visualization, EuroVis 2006, Lisbon, Portugal, May 8-10, 2006 2006 3-905673-31-2 EuroVis Eurographics Association http://diglib.eg.org/handle/10.2312/399 db/conf/vissym/eurovis2006.html