@inproceedings{heckman-iros-07,
  author =	 {Nicholas Heckman and Jean-Fran\c{c}ois Lalonde and
                  Nicolas Vandapel and Martial Hebert},
  booktitle =	 {IEEE/RSJ International Conference on Intelligent
                  Robots and Systems},
  title =	 {Potential negative obstacle detection by occlusion
                  labeling},
  year =	 2007
}