@InProceedings{steger:99,
  author =       "Carsten Steger",
  title =        "Extraction of Watersheds from {DTM} and Images with
                  Subpixel Precision",
  volume =       "XXXII, Part 3--2W5",
  pages =        "55--60",
  booktitle =    "International Archives of Photogrammetry and Remote
                  Sensing",
  year =         "1999"
}