ENERGETIC PARTICLE COMPOSITION VARIATIONS DURING THE MARCH 1991 EVENTS MEASURED WITH THE ULYSSES EPAC INSTRUMENT - KRUPP,N; KEPPLER,E; FRANZ,M; KORTH,A; WITTE,M; MOUSSAS,X; BLAKE,JB; NAIDU,K; QUENBY,JJ; WOCH,J; BALOGH,A; BAME,S (GEOPHYSICAL RESEARCH LETTERS, 1992)