@techreport{Wallis-shortliffe82,
  author	= {Wallis, J. W. and Shortliffe, E. H.},
  year		= {1982},
  title		= {Explanatory Power for Medical Expert Systems: Studies in the Representation of Causal Relationships for Clinical Consultation},
  number	= {STAN-CS-82-923},
  note		= {Heuristics Programming Project. Department of Medecine and Computer Science},
  institution	= {Stanford University}
}