@ARTICLE{Boehme-RAS-2003,
  author = {Boehme, Hans-Joachim and Wilhelm, Torsten and Key, Juergen and Schauer,
    Carsten and Schroeter, {\relax Ch}ristof and Gross, Horst-Michael
    and Hempel, Torsten},
  title = {An Approach to Multi-Modal Human-Machine Interaction for Intelligent
    Service Robots},
  journal = {Robotics and Autonomous Systems (RAS)},
  year = {2003},
  volume = {44},
  pages = {83--96}
}