1. Born, M. and Huang, K., Dynamic Theory of Crystal Lattices, Oxford: Clarendon, 1954. Translated under the title Dinamicheskaya teoriya kristallicheskikh reshetok, Moscow: Inostrannaya Literatura, 1958, p. 488.
2. Waddingthon, T.C., Adv. Inorg. Chem. Radiochem., 1959, vol. 1, p. 157.
3. Mamulov, S.A., Sposoby vychisleniya energii reshetki kristallov (Procedures for Calculating Crystal Lattice Energies), Stalinsk, 1961, p. 191.
4. Tosi, M., Solid State Phys., 1964, vol. 16, p. 1.
5. Ladd, M.F.C. and Lee, W.H., in Progress in State Chemistry, New York, 1964, vol. 1, p. 37; 1965, vol. 2, p. 378.