About KOYAMA RYOTA
About 協同組合研究誌にじ
About cooperative association
About agricultural science
About education and training
About agricultural management
About modification
About information society
About information technologization
About aging
About cultivation of human resources
About agricultural cooperative
About Agricultural economy,agricultural management
About 協同
About 組合
About 地域社会
About 農学
About 農協