8Nelson. Information and consumer behavior. Journal of Political Economy. 1970, 78 (2) : 311 - 29.
9Tietzel, M. , & Weber, M. Von Betru'" gem, Blendern and Opportunisten. Zeitschrift fu"r Wirtschaftspolitik, 1991, 40:109 ~ 137.
10Caswell, J. A. , Bredahl, M. E. , Hooker, N. M. How quality management systems are affecting the food industry. Review of Agricultural Eco- nomics. 1998 (20):547 -557.