Factor four : doubling wealth--halving resource use : the new report to the Club of Rome / Ernst von Weizsäcker, Amory B. Lovins, and L. Hunter Lovins. Weizsäcker, Ernst U. von (Ernst Ulrich), 1939- Lovins, Amory B., 1947- jt. aut. Lovins, L. Hunter, 1950- jt. aut. Club of Rome. Energy conservation. Conservation of natural resources. 338.06 WEF Includes bibliographical references (p. [300]-307) and index. London : Earthscan, 1998 (2000 printing). 1998 (2000 printing). 1998 Text xxix, 322 p., [8] p. of plates : eng