APA

Porter M. E., . (1991). Michael E. Porter on competition and strategy. Boston: A Harvard Business.

Chicago

Porter Michael E, . 1991. Michael E. Porter on competition and strategy. Boston: A Harvard Business.

Harvard

Porter M. E., . (1991). Michael E. Porter on competition and strategy. Boston: A Harvard Business.

MLA

Porter Michael E, . Michael E. Porter on competition and strategy. Boston: A Harvard Business. 1991.