@CONFERENCE{Butkiewicz-SPIE2007,
  author = {Thomas Butkiewicz and Remco Chang and Zachary Wartell and William
    Ribarsky},
  title = {Analyzing sampled terrain volumetrically with regard to error and
    geologic variation},
  year = {2007},
  editor = {Robert F. Erbacher and Jonathan C. Roberts and Matti T. Gr\"{o}hn
    and Katy B\"{o}rner},
  volume = {6495},
  number = {1},
  pages = {64950O},
  publisher = {SPIE},
  doi = {10.1117/12.718019},
  eid = {64950O},
  journal = {Visualization and Data Analysis 2007},
  location = {San Jose, CA, USA},
  numpages = {10},
  url = {http://link.aip.org/link/?PSI/6495/64950O/1}
}