1. Faculty of Human Sciences, Osaka University of Economics, 2-2-8 Oosumi, Higashi-Yodogawa-ku, Osaka 533-8533, Japan
2. Faculty of Economics, Shiga University, 1-1-1 Banba, Hikone, Shiga 522-8522, Japan
3. Graduate School of Management, Kyoto University, Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501, Japan