PORTER MICHAEL. (2004). COMPETITIVE STRATEGY: TECHNIQUES FOR ANALYZING INDUSTRIES AND COMPETITORS. THE FREE PRESS.
Chicago-referens (17:e uppl.)PORTER MICHAEL. COMPETITIVE STRATEGY: TECHNIQUES FOR ANALYZING INDUSTRIES AND COMPETITORS. NEW YORK: THE FREE PRESS, 2004.
MLA-referens (9:e uppl.)PORTER MICHAEL. COMPETITIVE STRATEGY: TECHNIQUES FOR ANALYZING INDUSTRIES AND COMPETITORS. THE FREE PRESS, 2004.
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