Porter, M. E. (1980). Competitive strategy: techniques for analyzing: Industries and competitors. Collier Macmillan.
Cita Chicago (17th ed.)Porter, Michael E. Competitive Strategy: Techniques for Analyzing: Industries and Competitors. London: Collier Macmillan, 1980.
Cita MLA (9th ed.)Porter, Michael E. Competitive Strategy: Techniques for Analyzing: Industries and Competitors. Collier Macmillan, 1980.
Atenció: Aquestes cites poden no estar 100% correctes.