1. School of Economics, Fudan University, 618–600 GuoQuan Road, Shanghai 200433, China and Chinese University of Hong Kong, 929 Esther Lee Building, Shatin, Hong Kong.
2. Research Department, Federal Reserve Bank of Minneapolis, 90 Hennepin Avenue, Minneapolis, MN 55401.
3. Department of Economics, University of Zurich, Mühlebachstrasse 86, CH-8008 Zurich.