D.E.Bainum1,J.Rapaport1,C.D.Goodman2,D.J.Horen2, C.C.Foster3,M.B.Greenfield4,C.A.Goulding4 Ohio University, Athens, OH1 Oak Ridge National Laboratory, Oak Ridge, TN2 Indiana University, Bloomington, IN3 United States of America2
Physical Review Letters44(1980)1751