1. The Hitchhiker's Guide to the Galaxy;Adams,1980
2. Babbage, Charles. For information, contact the Charles Babbage Institute, University of Minnesota.
3. Many-Valued Logics;Bolc,1992
4. An Investigation of the Laws of Thought, on Which Are Founded the Mathematical Theories of Logic and Probabilities;Boole,1854
5. An Investigation of the Laws of Thought, on Which Are Founded the Mathematical Theories of Logic and Probabilities;Boole,1951