Labuschagne W, Heidema J and Britz K (2013): Supraclassical Consequence Relations: Tolerating Rare Counterexamples, in AI 2013: Advances in Artificial Intelligence, Volume 8272 of the series Lecture Notes in Computer Science pp 326-337.

Britz K, Heidema J, and Labuschagne WA (2007): A modal perspective on preferential entailment. 50th Annual Congress of the South African Mathematical Society, University of Cape Town, South Africa, October 2007. (Presented by Britz.)

Labuschagne WA, Heidema J and Britz K (2007): Abduction explained. Workshop on Logic and Multi-Agent Systems, University of Otago, New Zealand, 15-16 February 2007. (Presented by Labuschagne.)

Van der Westhuizen PL, van der Poll JA, and Labuschagne WA (2006): Templated revision. SAICSIT 2006: Annual conference of the South African Insitute of Computer Scientists and Information Technologists, Cape Winelands, South Africa, October 2006. (Presented by Van der Westhuizen.)

Labuschagne WA and Heidema J (2005): Natural and artificial cognition: On the proper place of reason. Annual Conference of the Philosophical Society of South Africa, University of Kwazulu–Natal, South Africa, January 2005. (Presented by Heidema.)

van Ditmarsch HP and Labuschagne WA (2003): Dynamic doxastic logic for defeasible belief revision. 12th International Congress on Logic, Methodology, and Philosophy of Science, Oviedo, Spain, August 2003. (Presented by van Ditmarsch.)

Labuschagne WA, Ferguson D, Heidema J, Meyer TA, and van der Westhuizen PL (2002): Information templates — A useful data structure for applied logic. LAMAS: The Otago Workshop on Logic and Multi-Agent Systems, October 2002. (Presented by Labuschagne.)

Labuschagne WA and Ferguson D (2002): Information-theoretic semantics for epistemic logic. LOFT5 — the Fifth Conference on Logic and the Foundations of Game and Decision Theory, Torino, Italy, June 2002. (Presented by Ferguson.)

Meyer TA, Labuschagne WA and Heidema J (1998): Semantic multiple contraction. Logic Colloquium 1998: The 1998 ASL European Summer Meeting, Prague, Czech Republic 9-15 Aug 1998. (Presented by Meyer.)

Meyer T, Labuschagne WA and Heidema J (1998): Bundle contraction. 41st SAMS Conference, Johannesburg, South Africa 25-27 June 1998. (Presented by Meyer.)

Meyer T, Labuschagne WA, Burger IC and Heidema J (1998): Revising epistemic states. 41st SAMS Conference, Johannesburg, South Africa 25-27 June 1998. (Presented by Meyer.)

Labuschagne WA and van der Merwe AJ (1996): Theory meets practice: Using Smith's normalisation in complex systems. In Ram V (ed): Proc. SAICSIT 1996 National Research and Development Conference — Industry Meets Academy. University of Natal Press, Pietermaritzburg, South Africa. (Presented by Van der Merwe.)

Heidema J, Labuschagne WA, Meyer T and Rosenblatt H (1995): A power-order semantics for nonmonotonic logic. Logic Colloquium 95: The 1995 ASL European Summer Meeting, Haifa, Israel, 9-18 August 1995. (Presented by Labuschagne.)

Rosenblatt H, Meyer T, Labuschagne WA and Heidema J (1995): Power-order semantics for nonmonotonic logic I. SAICSIT Symposium, Pretoria, South Africa, 25-26 May 1995. (Presented by Rosenblatt.)

Meyer T, Rosenblatt H, Labuschagne WA and Heidema J (1995): Power-order semantics for nonmonotonic logic II. SAICSIT Symposium, Pretoria, South Africa, 25-26 May 1995. (Presented by Meyer.)

Meyer T, Labuschagne WA and Heidema J (1995): Power-orderings as a generalisation of minimal model semantics. In Cantu et al. (eds): 8th International Symposium on Artificial Intelligence, Monterrey, Mexico, ITESM 394-401. (Presented by Meyer.)

Heidema J and Labuschagne WA (1991): Compatibility in deductive databases. 9th International Congress of Logic, Methodology and Philosophy of Science, Uppsala, Sweden, 7-14 August 1991. (Presented by Labuschagne.)

Labuschagne WA and Heidema J (1988): The measurement of semantic information. In Lasker GE (ed): Advances in Computer Science, Proceedings of the 4th International Conference on Systems Research, Informatics, and Cybernetics, Baden-Baden, West Germany, 15-21 Aug 1988, International Institute for Advanced Studies in Systems Research and Cybernetics, Windsor, Ontario, Canada 10-16. (Presented by Labuschagne.)