6Harbergor. A. Monopoly and Resource Allocation. American Economic Journal(May),1954.
7Joskow. P. Vertical Integration and Long-term Contracts. Journal of Law, Economics and Organization (Fall),1985.
8Joskow.P Asset Speci-ficity and the Structure of Vertical Relationships: Empirical Evidence.Journal of Law, Economics and Organiz- ation (Spring),1988.
9Marglin. S.A. What Do Bosses Do? The Origin and Functions of Hierarchy in Capitalist Production.Review of Radical Political Economics,1974.
10Penrose. B. The The-ory of the Growth of the Firm. New York:Oxford University Press,1995.