1. 2Cracknell, A. P., Crystals and Their Structures, Pergamon, New York, 1969, pp.1-25.
2. 4Love, A. E. H., A Treatise on the Mathematical Theory of Elasticity, 4th ed.Cambridge Univ. Press, London, 1927, pp.157-161.
3. 5Lekhmjtskii, S. G., Theory of Elasticity of an Anisotropic Body, Mir Publishers, Moscow, 1981, pp.39-43.