1. A. A. Logunov and A. N. Tavkhelidze, Nuovo Cimento,29, 380 (1963).
2. V. G. Kadyshevsky, Nucl. Phys. B,6, 125 (1968).
3. I. T. Todorov, Phys. Rev.,113, 235 (1963).
4. I. V. Amirkhanov, G. V. Grusha, and R. M. Mir-Kasimov, Preprint JINR E2-9767, Dubna (1977).
5. I. V. Amirkhanov, G. V. Grusha, and R. M. Mir-Kasimov, Preprint JINR E2-10351, Dubna (1977).