Far-infrared optical excitations in multiferroic TbMnO3M. Schmidt, Ch. Kant, T. Rudolf, F. Mayr, A. A. Mukhin, A. M. Balbashov, J. Deisenhofer and A. LoidlEur. Phys. J. B, 71 3 (2009) 411-418DOI: https://doi.org/10.1140/epjb/e2009-00215-3