5Jeffrey, S Royer.. The Industrialization of Agriculture Vertical Coordination in US Food System, Ashgate Publishing Limited Gower House, 1998.
6WiUiamson, O E : Markets and Hierarchies: Analysis and Antitrust Implications, New York: Free Press, 1975.
7David, A ,Hennessy, Y :Contractual Relations, Control and Quality in the Hog Sector, Review of Agricultural Economics, Volume 21, No. 1, 1999, pp52- 67.
