1. P. S. Fiske, W. J. Nellis, M. Lipp, H. Lorenzana, L-413, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
2. M. Kikuchi and Y. Syono, Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-ku Sendai 980-77, Japan.