50-500 MeV gamma-ray emission in the early phase of SN1987A - Sood, RK; Thomas, J; Waldron, L; Manchandra, RK; Ubertini, P; Bazzano, A; la, Padula C; Rochester, G; Sumner, TJ; Frye, G; Jenkins, T; Koga, R; et al. (AIPC, 1988)