1. Graduate School of Business Doshisha University Karasuma‐Imadegawa, Kamigyo‐ku Kyoto Japan
2. Faculty of Economics Ritsumeikan University Noji Higashi 1 chome Kusatsu Shiga Japan
3. College of Current Business Nagoya Sangyou University Yamanota 3255‐5, Arai‐chyou Owariasahi Aichi Japan