1. K. K. Chow, W. Levasen, and C. A. McAuliffe, ref1,pp35-177.
2. J. G. Verkade and K. J. Coskran, "Organic Phosphorus Compounds", Vol.2, G. M. Kosolapoff and L. Maier,Ed. Wiley-Interscience, New York, N.Y.1972, Chapter 3B, pp1-187.
3. The trans-influence: its measurement and significance