8MINEVA T,SICILIA E,RUSSO N.Density-Functional Approach to Hardness Evaluation and Its Use in the Study of the Maximum Hardness Principle[J].J Am Chem Soc,1998,120:9053.
9Moustafa A H,Wirschun W,Freyhardt C C,et al,Ene reactioms and[2+2]cycloadditions of nitrilium sslts with alkenes[J].Journal Fur Praktische Chemie,1977,339:615-622.
10Frisch M J,Trucks G W,Schlegel H B,et al.Gaussian 98,Pittsburgh PA:Gaussian Inc,1998.
