Jasay, A. D. (1989). Social contract, free ride: Study of the public-goods problem. Oxfod University Press.
Lua i Stíl Chicago (17ú heag.)Jasay, Anthony De. Social Contract, Free Ride: Study of the Public-goods Problem. New York: Oxfod University Press, 1989.
Lua MLA (9ú heag.)Jasay, Anthony De. Social Contract, Free Ride: Study of the Public-goods Problem. Oxfod University Press, 1989.
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