1. L. Pauling,The Nature of the Chemical Bond, Cornell University Press, New York (1960).
2. K. Mislow,Introduction to Stereochemistry, Benjamin, New York (1966).
3. R. McWeeny,Coulsons's Valence, Oxford University Press, London (1979).
4. M. Randic and Z. B. Maksic,Chem. Rev.,72, 43, (1972).
5. R. C. Haddon,J. Am. Chem. Soc.,108, 2837–2842, (1986).