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2. Bell, J. L. (1977).Boolean-valued models and independence proofs in set theory. Oxford University Press, New York.
3. Chevalley, C. C. (1954).The algebraic theory of spinors. Columbia University Press, New York.
4. Feynman, R. P. (1965).The character of physical laws. Massachusetts Institute of Technology, Cambridge, Massachusetts.
5. Finkelstein, D. (1969). “Space-Time Code,”Physical Review,184, 1261; (1982). “Cosmological Choices,”Synthese, to appear.