1. Office of Operations, United States International Trade Commission, Washington, DC 20436)
2. Office of Economics, United States International Trade Commission, Washington, DC 20436 (e-mail: )
3. Columbia Business School, Uris Hall, 3022 Broadway, Room 619 New York, NY 10027, Tsinghua Center for International Economic Research (CIER), and NBER (e-mail: )