NEW NON LINEAR EXCITATIONS IN (CD3)4NMnCl3 (TMMC) J.P. BOUCHER, M. REMOISSENET, R. PYNN et L.P. REGNAULT J. Phys. Colloques, 50 C3 (1989) C3-29-C3-32 DOI: 10.1051/jphyscol:1989304