Porter, M. E. (1980). Competitive strategy: techniques for analyzing: Industries and competitors. Collier Macmillan.
Chicago-viite (17. p.)Porter, Michael E. Competitive Strategy: Techniques for Analyzing: Industries and Competitors. London: Collier Macmillan, 1980.
MLA-viite (9. p.)Porter, Michael E. Competitive Strategy: Techniques for Analyzing: Industries and Competitors. Collier Macmillan, 1980.
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