Porter, Michael E. Competitive strategy : techniques for analyzing industries and competitors/ Michael E. Porter - New York : Free Press , c1980 - xxi, 368 pages : illustrations ; 23cm. Includes bibliographical references and index. ISBN: 978-0684-84148-9 Subjects--Topical Terms: 1. Competition2. Industrial management. Dewey Class. No.: Circ. 658 P844c 1980