Porter, Michael E., 1947- Competitive advantage : creating and sustaining superior performance / Michael E. Porter. - New York : London : Free Press ; Collier Macmillan, c1985. - xviii, 557 p. : ill. ; 25 cm. Includes index. ISBN: 0029250900 LCCN: 83049518 Subjects--Topical Terms: Competition.Industrial management. Dewey Class. No.: 658 POR