6Unnevehr L,N Hirschhom.Food Safety Issues in the DevelopingWorld[R].Washington DC:World Bank.
7WHO.Food Safety and Food-Borne Illness(Fact sheet No.237)[EB/OL].[2007-03].http://www.who.int/mediacentre/factsheets/fs237/en/index.html.
8Akerlof G.The Market for Lemons:Quality Uncertainty and theMarket Mechanism[J].Quarterly Journal of Economics,1970(84).
9Frank S D,D R Henderson.Transaction Costs as Determinants ofVertical Coordination in the US.Food Industries[J].AmericanJournal of Agricultural Economics,1992,74(4).
10Hennessy,D.A.,J.D.Lawrence.Contractual Relations,Control,and Quality in the Hog Sector[J].Review ofAgricultural Economics,1999(1).