1. Agha, G. 1990. Concurrent object-oriented programming. Communications of the ACM 33(9): 125–141.
2. Bratko, I., Mozetic, I. & Lavrac, N. 1989. KARDIO. A study in deep and qualitative knowledge for expert systems. 260 pp. The MIT Press, Cambridge, Massachusetts.
3. Bryant, J.P., Chapin, F.S.III & Klein, D.R. 1983. Carbon/nutrient balance of boreal plants in relation to vertebrate herbivory. Oikos 40: 357–368.
4. Cohen, P.R., Greenberg, M.L., Hart, D.M. & Howe, A.E. 1989. Trial by fire: understanding the design requirements for agents in complex envionments. AI Magazine 10(3): 34–48.
5. DeKleer, J., & Williams, B.C. 1987. Diagnosing multiple faults. Artificial Intelligence 32: 97–130.