5Olson, Mancur: The Logic of Collective Action, Cambridge: Harvard University Press, 1965.
6Williamson, Oliver, Markets and Hierarchies: Analysis and Antitrust Implication . New York: The Free Press, 1975.
7Cheung, Steven, "The Contractual Nature of the Firm". Journal of Law and Economics, 26: 1-21, 1983.
8Andrew M. Condon: The Methodology and Requirements of a Theory of Cooperative Enterprise , in "Cooperative Theory: New Approaches" ( Agricultural Cooperative Service Report 18) , Jeffery S. Royer edited, Washington, D. C. : USDA, 1987.
9F. Robokta: A Theory of Cooperation , in "Agricultural Cooperation: Selected Readings", M. A. Abrahamsen and C. L. Scroggs edited, Minneapolis: University of Minnesota Press, pp. 121-142,1957.
10R. E. Torgerson, B. Reynolds, T. W. Gray: "Evolution of Cooperative Thought: Theory and Purpose" , Journal of Cooperatives, 13: 1--20, 1998.
