COMETARY WATER-GROUP IONS IN THE REGION SURROUNDING COMET GIACOBINI-ZINNER - DISTRIBUTION-FUNCTIONS AND BULK PARAMETER ESTIMATES - STAINES, K; BALOGH, A; COWLEY, SWH; HYNDS, RJ; YATES, TS; RICHARDSON, IG; SANDERSON, TR; WENZEL, KP; MCCOMAS, DJ; TSURUTANI, BT (PLANETARY AND SPACE SCIENCE, 1991)