North Holland, 1989
Buku Teks SO
Walker, Terry
The S. Klien News Letter, 1986
Buku Teks SO
Alty, J.L.
NCC Publications, 1984
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edited by, Frederick Hayes-Roth, Donald A. Waterman and Douglas Lenat
Addison-Wesley, 1983
Buku Teks SO
Shapiro, Alen D.
Addison-Wesley, 1987
Buku Teks SO