1. Gray,G.W., “Molecular structure and the properties of liquid crystals”. Academic Press, London,(1962)
2. lb. ibid p-192–196 (unpublished work).
3. lC. ibid p-199, J.Chem.Soc., 396, (1957).
4. Brown G.H. and Shaw W.G. The mesomorphic state, Chem. Rev. Vol. 57 (6), (1957).
5. Daniel Berg 11aa l,Acad.Sci.Natl.Res.Council, publ.No. 1356, 23–5, (1965), pub1.1966.