NEW MODEL OF SINGLET-GROUND-STATE MAGNET WITH EXCHANGE COUPLING : APPLICATION TO CsFeCl3 M. Chiba, Y. Ajiro, K. Adachi et T. Morimoto J. Phys. Colloques, 49 C8 (1988) C8-1445-C8-1446 DOI: 10.1051/jphyscol:19888663