Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Mizushima Kazuya,Historical Change of the Mutualism in the Insurance System,国民経済雑誌,03873129,神戸大学経済経営学会,1992-05,165,5,1-18,https://cir.nii.ac.jp/crid/1390853649855332736,https://doi.org/10.24546/00174829