@InProceedings{Grimm:2004:VOB,
 author = "S{\"o}ren Grimm and Stefan Bruckner and Armin Kanitsar and E. Gr{\"o}ller",
 title =  {Flexible Direct Multi-Volume Rendering in Interactive Scenes},
 booktitle =    "Vision, Modeling, and Visualization",
 pages =        "? -- ?",
 year =         "2004",
 }