by TOVMASSIAN, H. M, HOVHANESSIAN, R. KH, EFREMIAN, R. A, KHODJAYANTS, YU. M, KRMOYAN, M. N, KASHIN, L. A, HUGUENIN, D, ROMANENKO, YU, ALEXANDROV, A. P
Published in Astrophysics and space science (01.05.1990)