1. Cf.,e.g.,I. Segai,:Phys. Scr.,24, 827 (1981).
2. P. Roman:Introduction to Quantum Field Theory (John Wiley and Sons., Inc., New York, N.Y., 1969).
3. N. N. Bogolubov, A. A. Lugonov andI. T. Todorov:Introduction to Axiomatic Quantum, Field Theory (W. A. Benjamin, London, 1975).
4. A. S. Wightman: inHigh-Energy Electromagnetic Interactions and Field Theory, edited byM. Lévy (Gordon and Breach, New York, N.Y., 1967).
5. M. Banai:J. Math. Phys. (N.Y.), to appear;