1. Bratko, I. (1986). Prolog programming for Artificial Intelligence. Wokingham: Addison Wesley.
2. Byrd, L. (1980). Understanding the control flow of PROLOG programs. In S.-A. Tarnlund (Ed.), Proceedings of the Logic Programming Workshop, pp. 127?138. Research Paper 151, Department of Artificial Intelligence, University of Edinburgh.
3. Clocksin, W. F. and Mellish, C. S. (1984). Programming in Prolog. Berlin: Springer Verlag.
4. Dewar, A. D. and Cleary, J. G. (1986). Graphical display of complex information within a Prolog debugger. International Journal of Man-Machine Studies, 25, 503?511.
5. Eisenstadt, M. and Brayshaw, M. (1990). A fine-grained account of Prolog execution for teaching and debugging. Instructional Science, 19(4/5), 407?436.