1. L. Byrd, Understanding the control flow of Prolog programs, in: S.-A. Tärnlund (Ed.), Logic Programming Workshop, Debrecen, Hungary, 1980
2. M. Calejo, A framework for declarative Prolog debugging, Ph.D. Thesis, New University of Lisbon, Portugal, March 1992
3. M. Ducassé, Opium: an extendable trace analyser for Prolog, in: A. Bossi, Y. Deville (Eds.), The Journal of Logic programming, Special issue on Synthesis, Transformation and Analysis of Logic Programs, 1999
4. Logic programming environments: dynamic program analysis and debugging;Ducassé;The Journal of Logic Programming,1994
5. M. Eisenstadt, A powerful Prolog trace package, in: Proceedings of the Sixth European Conference on Artificial Intelligence, September 1984, North-Holland, Amsterdam, 1985