1. P. G. de Gennes, Physics of Liquid Crysteds (Clarendon, Oxford, England, 1974).
2. S. Chandrasekhar, Liquid Crystals (Cambridge Univeraity, Cambridge, England, 1977).
3. D. A. Balzarini, Phys. Rev. Lett. 25, 914 (1970).PRLTAO0031-9007
4. M. Brunet‐Germain, C. R. Acad. Sci. (Paris) 271, 1075 (1970).
5. N. V. Madhusudana, R. Shashidhar, and S. Chandrasekhar, Mol. Cryst. Liq. Cryst. 13, 61 (1971).MCLCA50026-8941