The power of unreasonable people : how social entrepreneurs create markets that change the world / John Elkington, Pamela Hartigan. Elkington, John. Hartigan, Pamela. Social entrepreneurship. Social change. HD60 .E45 2008 361.70688 22 ELP Includes bibliographical references and index. Boston, Mass. : Harvard Business School Press, c2008. c2008. 2008 Text xviii, 242 p. ; eng