1. CERN, TE Department, Genève 23, CH-1211, Switzerland
2. Fermi National Accelerator Laboratory, Batavia, IL 60510, USA
3. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
4. CEA, Saclay, 91400, France
5. KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan