Porter, M. E. (1990). The competitive advantage of nations. Macmillan.
Chicago Style aipamenaPorter, Michael E. The Competitive Advantage of Nations. London: Macmillan, 1990.
MLA aipamenaPorter, Michael E. The Competitive Advantage of Nations. Macmillan, 1990.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.