@incollection{ABELSON73,
  author	= {Abelson, R. P.},
  editor	= {Schank, Roger C. and Colby, K.},
  year		= {1973},
  title		= {The Structure of Belief Systems},
  booktitle	= {Computer Models of Thought and Language},
  publisher	= {W. H. Freeman Co.},
  address	= {San Francisco}
}