High-frequency dynamics and the spin-glass transition D. Bitko, N. Menon, S. R. Nagel, T. F. Rosenbaum and G. Aeppli Europhys. Lett., 33 6 (1996) 489-494 Published online: 01 September 2002 DOI: 10.1209/epl/i1996-00368-1