[1] Univ So Calif, Dept Econ, Los Angeles, CA 90089 USA
[2] NBER, Cambridge, MA USA
[3] City Univ Hong Kong, Kowloon Tong, Hong Kong, Peoples R China
[4] CESifo, Munich, Germany
[5] Nederlandsche Bank, POB 98, NL-1000 AB Amsterdam, Netherlands
[6] Univ Groningen, Fac Econ & Business, POB 800, NL-9700 AV Groningen, Netherlands