1. Aharonyan, F. A., Atoyan, A. M., and Sunyaev, R. A.: 1980, ?The Annihilation Spectrum of Relativistic Electron-Positron Plasma?, Yerevan, Physics Institute, preprint 432(39)-80.
2. Aharonyan, F. A., Atoyan, A. M., and Sunyaev, R. A.: 1983,Astrophys. Space Sci. 93, 229.
3. Barat, C., Hurley, K., Niel, M., Vedrenne, G., Evans, W. D., Fenimore, E. E., Klebesadel, R. W., Laros, J. G., Cline, T. L., Estulin, I. V., Zenchenko, V. M., and Kurt, V. G.: 1984a,Astrophys. J. 280, 150.
4. Barat, C., Hurley, K., Niel, M., Vedrenne, G., Mitrofanov, I. G., Estulin, I. V., Zenchenko, V. M. and Dolidze, V. Sh.: 1984b,Astrophys. J. 286, L11.
5. Burns, M. L. and Harding, A. K.: 1983, in M. L. Burns, A. K. Harding, and R. Ramaty (eds.),Positron?Electron Pairs in Astrophysics, AIP Conf. Proc., No. 101, New York, p. 416.