1. N. D. Sokolov, U. F. N., 57, 205 (1955).
2. D. N. Shigorin, in: Problems of Physical Chemistry [in Russian], Part 1, Goskhimizdat, Moscow (1958), p. 173; in: The Hydrogen Bond [in Russian], Nauka, Moscow (1964), p. 195; V. G. Plotnikov and D. N. Shigorin, Zh. F. Khim., 39, 2608 (1965).
3. R. Nyquist, Spectrochim. Acta, 19, 1655 (1963).
4. A. Baker and A. Schulgin, J. Amer. Chem. Soc., 80, 5358 (1957).
5. A. E. Lutskii, Zh. Strukt. Khim., 7, 453 (1966).