@Article{SCI:Kni2003a,
  author =    "J.M. Kniss and S. Premoze and C.D. Hansen and P.
              Shirley and A. McPherson",
  title =     "A Model for Volume Lighting and Modeling",
  journal =   "{IEEE} Transactions on Visualization and Computer
              Graphics",
  volume =    "9",
  number =    "2",
  year =      "2003",
  month =     "April - June",
  url =       "http://www.sci.utah.edu/publications/jmk03/kniss_tvcg03_volshade.pdf",
}