1. See the review by T. Matsubara, Jpn. J. Appl. Phys. 24, suppl. 24-2, 1 (1985).
2. J. Petzelt, Phase Transitions 2, 155 (1981).
3. H. Z. Cummins and A. P. Levanyuk, eds., “Light Scattering Near Phase Transitions” (North-Holland, Amsterdam, 1983).
4. V. A. Golovko and A. P. Levanyuk, Sov.-Phys. JETP 54, 1217 (1981).
5. R. Zeyher and W. Finger, Phys. Rev. Lett. 49, 1833 (1982).