1Caswell,J. A. ,Brudahl,M. E. & Hooker,N. H. How quality management metasystems are affecting the food industry? [J] .Review of Agricultural economics, 1998, (20) .
2Akerlof, G. A. The Market for Lemons: Qualitative Uncertainty and the Market Mechanism [J] . Quarterly journal of Economics, 1970, (84) .