1. III;Rice;Chem SOC,1987
2. By;Jackmann;Bother Am Chem SOC,1962
3. in press;Jiao;Chem SOC Faraday Trans Chem Engl Chem Engl Chem Int Engl Chem SOC,1994
4. submitted;Schleyer;Am Chem SOC,1995
5. The experimental data taken from : a;Rosenstock;Phys Chem Ref Rev,1993