Toshihiko Takemura The Research Institute for Socionetwork Strategies, Kansai University   3-3-35 Yamate-cho Suita, Osaka 564-8680 Japan   takemura@rcss.kansai-u.ac.jp   http://www.rcss.kansai-u.ac.jp/~takemura/           JEL Areas: C4 : Econometric and Statistical Methods: Special Topics D0 : Microeconomics: General