Cita APA (7th ed.)

Porter, M. E. (1980). Competitive strategy: Techniques for analyzing industries and competitors. Free Press.

Cita Chicago (17th ed.)

Porter, Michael E. Competitive Strategy: Techniques for Analyzing Industries and Competitors. New York: Free Press, 1980.

Cita MLA (9th ed.)

Porter, Michael E. Competitive Strategy: Techniques for Analyzing Industries and Competitors. Free Press, 1980.