1. C. Kittel (1971), “An introduction to solid state physics”, Wiley India Press, 7th Edition, 117.
2. The Vibrational Spectrum and Specific Heat of Sodium
3. A.K. Ghatak and L.S. Kothari (1972), “An introduction to lattice dynamics”, chapter7, 132.
4. S.K. Mahna (1983), “Lattice dynamics and homology of alkali metal”, chapter2, 35.
5. Lattice dynamics of sodium on modified Bhatia's model