First Author:   Shiba Suzuki Faculty of Economics, Seikei University shiba.suzuki@econ.seikei.ac.jp   3-3-1, Kichijoji-Kitamachi Musashino-shi, 180-8633, Japan       Second Author: Hiroaki Yamagami Faculty of Economics, Seikei University yamagami@econ.seikei.ac.jp   Kichijoji-kitamachi, Kichijoji-kitamachi, 3-3-1 Kichijoji-kitamachi Musashino-shi, 180-8633, JAPAN   81422373578(Phone)