@ARTICLE{Wilhelm-RAS-2004,
  author = {Wilhelm, Torsten and Boehme, Hans-Joachim and Gross, Horst-Michael},
  title = {A Multi-Modal System for Tracking and Analyzing Faces on a Mobile
    Robot},
  journal = {Robotics and Autonomous Systems (RAS)},
  year = {2004},
  volume = {48},
  pages = {31--40},
  number = {1}
}