1. (a) P.R. Wells, Linear Free Energy Relationships, Academic Press, New York, 1968.
2. (b) L.P. Hammett, Physical Organic Chemistry, McGraw-Hill, New York, 1970.
3. (c) R.W. Taft, Prog. Phys. Org. Chem. 14 (1983) 247.
4. (d) T.H. Lowry, K.S. Richardson, Mechanism and Theory in Organic Chemistry, third ed., Harper and Row, New York, 1987, Chapters 3 and 4.
5. (e) J. March, Advanced Organic Chemistry, Wiley Interscience, New York, 1985.