1. Alexeenko, V. V., Chudakov, A. E., and Gulieva, E. N.: 1981,17th Int. Cosmic Ray Conf. Paris 2, 146.
2. Bloemen, J. B., Bennett, K., Bignami, G. F., Blitz, L., Caraveo, P. A., Gottwald, M., Hermsen, W.; Lebrun, F., Mayer-Hasselwander, H. A., and Strong, A. W.: 1983,18th Int. Cosmic Ray Conf. Bangalore, XG5-4.
3. Bulanov, S. V. and Dogiel, V. A.: 1974,Astrophys. Space Sci. 18, 305.
4. Caraveo, P. A., Bignami, G. F., Vigroux, L., and Paul, J. A.: 1984,Astrophys. J. 276, L45.
5. Cutler, D. J., Bergeson, H. E., Davis, J. F., and Groom, D. E.: 1981,Astrophys. J. 248, 1166.