1. Computability and Unsolvability;Davis,1958
2. The Undecidable;Davis,1965
3. Computers and Intractability: A Guide to the Theory of NP-Completeness;Garey,1979
4. Empirically-derived estimates of the complexity of labelling line drawings of polyhedral scenes;Parodi;Artif. Intell.,1998
5. A New Proof of the NP-Completeness of Visual Match;Rensink,1989