5Modigliani,F. And R. Brumbergff, Utility Analysis and the Consump- tion Function: An Interpretation of Cross-section Date [M]fl Kenneth, K. K. Post-Keynesian Economices. New Brunswick, N J: Rutgers U- niversity Press, 1954.
6Rust, Roland T. and Richard L. Oliver (2000),"Should We Delight the Customer" [J].Joural of the Academy of Marketing Science, 2000,28(1 ):86.