PORTER, M. E. (1980). Competitive strategy: Techniques for analyzing industries and competitors. The Free Press.
Chicago-čujuhus (17. p.)PORTER, Michael E. Competitive Strategy: Techniques for Analyzing Industries and Competitors. New York: The Free Press, 1980.
MLA-čujuhus (9. p.)PORTER, Michael E. Competitive Strategy: Techniques for Analyzing Industries and Competitors. The Free Press, 1980.
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