1. Bhagavantam, S. and Bhimasenachar, J.Current Science, 1944,13, 229.
2. Voigt, W.Lehrbuch der Kristallphysik, 1928.
3. Bergmann, L.Ultrasonics and Their Scientific and Technical Applications, 1938.
4. Atanasoff, J. V. and Hart, P. J.Phys. Rev., 1941,59, 85.
5. Suryanarayana, D.M.Sc. Thesis, Andhra University, 1944.