著者名,タイトル,雑誌名,ISSN,出版者名,出版日付,巻,号,ページ,URL,URL(DOI) Yoshida,Welfare-reducing entry in a differentiated Cournot oligopoly without costs,SSRN Discussion Paper,,,2017,,,,https://cir.nii.ac.jp/crid/1370569868912969088,