An Expert System in Reliability- Structure and Knowledge Representation. - Ivan Popchev; Neli Zlatareva (AIMSA, 1984)

EXTRACT: Integration of Factual and Procedural Descriptions through Object-Oriented Programming. - Ivan Popchev; I. Popov; Vasil Vasilev; V. Tadjer; G. Simov; Vesselin Bontchev (AIMSA, 1988)

A Formal Treatment of Non-Monotonic Reasoning. - Ivan Popchev; Neli Zlatareva (AIMSA, 1988)

A Logic for Truth Maintenance Reasoning. - Ivan Popchev; Neli Zlatareva; Marion Mircheva (AIMSA, 1990)

A Truth Maintenance Theory: An Alternative Approach. - Ivan Popchev; Neli Zlatareva; Marion Mircheva (ECAI, 1990)