1. (a) L. Pauling, J. Amer. Chem. Soc., 53, 3225 (1931)
2. (b) L. Pauling, The Nature of the Chemical Bond (Cornell University Press, Ithaca, N.Y., 1960) p. 341.
3. (a) T. Kiang and R.N. Zare, J. Amer. Chem. Soc., 102, 4024 (1980)
4. (b) A.R. Gregory and V. Malatesta, J. Org. Chem., 45, 122 (1980).
5. M. Green and J.W. Linnett, J. Chem. Soc., 4959 (1960). See also J.W. Linnett, (a) J. Amer. Chem. Soc., 83, 2643 (1961)