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3. See for example S. Coleman (1988).Nucl. Phys. B310, 864.
4. Gilbert G., Caltech report No. CALT-68-1524.
5. Morchio, G., and Stocchi, F. (1987). InFundamental Problems of Gauge Field Theory, (Erice 1985), Velo, G., and Wightman, A. S., eds. (Plenum, New York).