1. Benkler, Y. (2006).The wealth of networks: How social production transforms markets and freedom. New Haven, CT: Yale University Press.
2. Boyle, K. J. (2003). Contingent valuation in practice. In P. A. Champ, K. J. Boyle, & T. C. Brown (Eds.),A primer on nonmarket valuation(pp. 111–170). Norwell, MA: Kluwer Academic Publishers.
3. Carson, R. T. (1999).Contingent valuation: A user’s guide(Discussion Paper No. 99–26). Department of Economics, University of California. CA: San Diego.
4. Einhorn, M. A. (2004).Media, technology and copyright: Integrating law and economics. Northampton, MA: Edward Elgar.
5. Fisher, W. (2001). Theories of intellectual property. In R. Munzer Stephen (Ed.),New essays in the legal and political theory of property(pp. 168–200). Cambridge, MA: Cambridge University Press.