1. William S. Davis, Fundamental Computer Concepts (Reading, MA: Addison-Wesley, 1986), p. 2.
2. Stephen C. Kleene, Mathematical Logic (New York: John Wiley and Sons, 1967), eh. 5.
3. Douglas Downing and Michael Covington, Dictionary of Computer Terms (Woodbury, NY: Barren’s, 1986), p. 117. On the use of the term “heuristics” in the field of artificial intelligence, see Avron Barr and Edward A. Feigenbaum, The Handbook of Artificial Intelligence, vol. I (Reading, MA: Addison-Wesley, 1981), pp. 28-30, 58, 109.
4. Examples of expert systems may be found in Avron Ban and Edward A. Feigenbaum, The Handbook of Artificial Intelligence, vol. II (Reading, MA: Addison-Wesley, 1982).
5. A discussion of various kinds of expert systems may be found in James H. Fetzer, Artificial Intelligence: Its Scope and Limits (Dordrecht, The Netherlands: Kluwer Academic Publishers, 1990), pp. 180–191.