Porter, M. E. (1990). The competitive advantage of nations. Free Press.
Cita Chicago (17th ed.)Porter, Michael E. The Competitive Advantage of Nations. New York: Free Press, 1990.
Cita MLA (9th ed.)Porter, Michael E. The Competitive Advantage of Nations. Free Press, 1990.
Atenció: Aquestes cites poden no estar 100% correctes.