@incollection{Walhster81,
  author	= {Wahlster, Wolfgang},
  editor	= {Rieger, B.},
  year		= {1981},
  title		= {Implementing Fuzziness in Dialogue Systems},
  booktitle	= {Empirical semantics},
  publisher	= {Brockmeyer},
  address	= {Bochum}
}