1. Shallenberger, R. S., and Acree, T. E., Nature, 216, 480 (1967).
2. Warfield, R. B., Abstr. Papers 126th Meet. Amer. Chem. Soc., 15A (1954).
3. Pimentel, G. C., and McClellan, A. L., The Hydrogen Bond (W. H. Freeman and Co., San Francisco, 1960).
4. Solms, J., Vuataz, L., and Egli, R. H., Experientia, 21, 692 (1965).
5. Kaneko, T., J. Chem. Soc. (Japan), 59, 433 (1938).