Technical Report Number
The technical report presents a succinct description of the Justification Finder (if). The system if is a practical implementation of the theoretical ideas introduced elsewhere (see the technical report "On the Logic of Defeasible Reasoning", G Simari, WUCS-89-12). It is used to explore and validate those ideas. The system provides support for defeasible reasoning in a Prolog environment. The complete Prolog language is available and only a few new predicates are introduced extending the reserved words of the language. We will present the theoretical underpinnings of the system in a very terse manner. The reader is referred to  for a more complete account of defeasible reasoning.
Simari, Guillermo R., "A Justification Finder" Report Number: WUCS-89-24 (1989). All Computer Science and Engineering Research.