著者名,書名,版表示,出版者名,出版年,シリーズ名,番号,ISBN,ISSN,URL
"Kawada, Koichi",On the sum of four cubes and a product of k factors,,"Institute of Mathematics, University of Tsukuba",1993,Mathematical research note,,,,https://cir.nii.ac.jp/crid/1130855953824033546