1. College of Economics and Finance, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, Korea (e-mail: )
2. Department of Economics, University of Southern California, KAP 300, Los Angeles, CA 90089–0253 and School of Economics, Yonsei University, Seoul, Korea (e-mail: )
3. Department of Economics, University of Southern California, KAP 300, Los Angeles, CA 90089–0253 (e-mail: )