1. Rady School of Management, University of California, San Diego, La Jolla, California 92093-0553;
2. Korea University Business School, Seongbok-gu, Seoul 136-701, Korea;
3. Haskayne School of Business, University of Calgary, Calgary, Alberta T2N 1N4, Canada;
4. Korea University Business School, Seongbok-gu, Seoul 136-701, Korea