@Article{Hladuvka-2002-CnG,
   author = "\bf{}Ji{\v r}{\'{\i}} Hlad{\accent23u}vka\rm{} and Eduard Gr{\"o}ller",
   title  = "Smallest 2nd-order Derivatives for Efficient Volume-Data Representation",
   journal = "Computers and Graphics",
   volume = 26,
   number = 2,
   pages =  "229--238",
   year   = 2002
}