著者名,論文名,雑誌名,ISSN,出版者名,出版日付,巻,号,ページ,URL,URL(DOI) CHU Y.,On the shortest arborescence of a directed graph,Science Sinica,,,1965,14,,1396-1400,https://cir.nii.ac.jp/crid/1570854175817997952,