1. Particle Data Group, Eur. Phys. J. C 15, 725 (2000).
2. R. A. Arndt, R. L. Workman, I. I. Strakovsky, and M. M. Pavan, nucl-th/9807087; submitted to Phys. Rev. C.
3. F. Nichitiu, Analiza de Fasa in Fizica Interactiilor Nucleare (Editura Akademiei RSR, Bucharest, 1980; Mir,Moscow, 1983).
4. S. S. Vasan, Nucl. Phys. B 106, 71 (1976).
5. M. G. Olsson, Phys. Rev. D 13, 2502 (1976).