Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

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