Nutter, J. Terry
(1983),
"Default Reasoning in A.I. Systems",
Technical Report 204
(Buffalo: SUNY Buffalo Department of Computer Science).
A
SNePS approach; uses Belnap 1992's 4-valued logic
SCI/ENGR Thesis Collection Thesis C58 1984 N98
Belnap, Nuel D., Jr.
(1992),
"A Useful Four-Valued Logic: How a Computer Should Think",
in
Anderson, Alan Ross;
Belnap, Nuel D., Jr.;
Dunn, J. Michael;
et al.
(1992),
Entailment: The Logic of Relevance and Necessity, Vol. II
(Princeton: Princeton University Press),
§81, pp. 506-542.