EXCHANGE SPIN WAVES AND THEIR MANIFESTATION IN TWO-MAGNON ABSORPTION AND RAMAN SCATTERING V. V. Eremenko, S. A. Zvyagin, Yu. G. Pashkevich, V. V. Pishko, V. L. Sobolev and S. A. Fedorov J. Phys. Colloques, 49 C8 (1988) C8-913-C8-914 DOI: 10.1051/jphyscol:19888415