1. University of California-Los Angeles Anderson School, 110 Westwood Plaza, Los Angeles, CA 90095 and National Bureau of Economic Research.
2. Massachusetts Institute of Technology Sloan School of Management, 50 Memorial Drive, E52-435, Cambridge, MA 02142 and National Bureau of Economic Research.
3. New York University Stern School of Business, 44 West 4th Street, Suite 9-190, New York, NY 10012-1126, Centre for Economic Policy Research, and National Bureau of Economic Research.
4. Stanford University Graduate School of Business, Stanford, CA 94305 and National Bureau of Economic Research.