BRI LLOUIN SCATTERING STUDY OF THE INCOMMENSURATE (ANTIFERROELECTRIC) PHASE TRANSITION IN SODIUM NITRITE T. Yagi, Y. Hidaka et K. Miura J. Phys. Colloques, 42 C6 (1981) C6-731-C6-733 DOI: 10.1051/jphyscol:19816214