1. F.J. Gilman, R. Kauffman: Phys. Rev. D 36 (1987) 2761
2. A.V. Kisselev, V.A. Petrov, in: Proc. of the XXIVth Reconres de Moriond, ed. J. Tran Than Van (Editions Fronti�res), 1989, p. 213
3. A.V. Kisselev, V.A. Petrov: Preprint IHEP 90-23, Protvino, 1990; Nuovo Cim. 105A (1992) 9; Teor. Mat. Fiz. 91 (1992) 234
4. V.I. Ogievetskii, I.V. Polubarinov: Zh. Eksp. Teor. Fiz. 45 (1963) 237, 966
5. J. Ashman et al.: Phys. Lett. B 206 (1988) 364; Nucl. Phys. B328 (1989) 1