National Bureau of Economic Research
Conference on Research in Income and Wealth
Edited by Carol Corrado, John Haltiwanger,
and Daniel Sichel
The University of Chicago Press, Chicago 60637
The University of Chicago Press, Ltd., London
© 2005 by the National Bureau of Economic Research
All rights reserved. Published 2005
Printed in the United States of America
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ISBN: 0-226-11612-3 (cloth)