1. R. Haag, Phys. Rev.,112, 669 (1958).
2. D. Ruelle, Helv. Phys. Acta,35, 147 (1962).
3. V. D. Koshmanenko, Dokl. Akad. Nauk SSSR,218, 753 (1974).
4. T. Kato, J. Funct. Anal.,1, 342 (1967).
5. V. D. Koshmanenko, Dokl. Akad. Nauk. SSSR,224, 277 (1975).