1. The tractability of subsumption in frame based description languages;Brachman,1984
2. An overview of the KL-ONE knowledge representation system;Brachman;Cogn. Sci.,1985
3. The complexity of concept languages;Donini,1991
4. Computers and intractability—A guide to the theory of NP-completeness;Garey,1979
5. Subsumption algorithms for concept description languages;Hollunder,1990