Porter, M. E. (1998). Competitive Strategy (ain.). Simon & Schuster UK Ltd.
Chicago Style aipamenaPorter, Michael E. Competitive Strategy. ain. Great Brit: Simon & Schuster UK Ltd, 1998.
MLA aipamenaPorter, Michael E. Competitive Strategy. ain. Simon & Schuster UK Ltd, 1998.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.