Optical Properties and Phenomenological Theory of Ferri-Ferri Phase Transitions in Antiferroelectric Liquid Crystals P. Gisse, M. Sidir, V.L. Lorman, R. Farhi, J. Pavel et H.T. NguyenJ. Phys. II France, 7 12 (1997) 1817-1828DOI: https://doi.org/10.1051/jp2:1997216