@techreport{weko_66105_1,
   author	 = "岩田,覚 and 永野,清仁",
   title	 = "劣モジュラ費用集合被覆問題",
   year 	 = "2009",
   institution	 = "京都大学, 東京工業大学",
   number	 = "3",
   month	 = "sep"
}