Noriaki Matsushima Graduate School of Business Administration, Kobe University   Rokkodai 2-1, Nada Kobe, Hyogo 657-8501 Japan   nmatsush@kobe-u.ac.jp   http://norick.sakura.ne.jp/index-e.html           JEL Areas: L1 : Market Structure, Firm Strategy, and Market Performance: General L2 : Firm Objectives, Organization, and Behavior: General