@InProceedings{heipke-etal:95b,
  author =       "Christian Heipke and Carsten Steger and Ralph
                  Multhammer",
  title =        "A Hierarchical Approach to Automatic Road Extraction
                  from Aerial Imagery",
  editor =       "Christian Heipke",
  series =       "Report No. 433",
  pages =        "29--39",
  booktitle =    "From Digital Images to Spatial Objects: Research and
                  Development Topics in Digital Photogrammetry",
  year =         "1995",
  address =      "Department of Geodetic Science and Surveying, The
                  Ohio State University, Columbus, OH",
  month =        dec
}