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2. E. R. Speer:Generalized Feynman Amplitudes (Princeton University Press, Princeton, N.J., 1969).
3. A. Erdelyi (Editor):Tables of Integral Transforms, Vol.2 (MacGraw-Hill Book Company, Inc., New York, N. Y., 1954), Chapt. VIII.
4. R. Glauber:Lectures in Theoretical Physics, Vol.1, edited byW. E. Brittin andL. G. Dunham (Interscience, New York, N. Y., 1959), p. 315.
5. E. Etim, A. Malecki andL. Satta:Phys. Lett. B,184, 99 (1987).