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)