1. a Faculty of Business Administration , Yokohama National University , 79-4, Tokiwadai, Hodogaya-Ku, Yokohama , 240-0067 , Japan
2. b Graduate School of Environmental Studies , Tohoku University , 6-6-20 Aramaki-Aza Aoba, Aoba-Ku, Sendai , 980-8579 , Japan
3. c Economy and Environment, The Institute for Global Environmental Strategies , Hayama , Kanagawa , 240-0115 , Japan
4. d Graduate School of Public Policy , University of Tokyo , Tokyo , Japan