@article{weko_60498_1,
   author	 = "Yuta,Tsuboi and Hisashi,Kashima and Shohei,Hido and Steffen,Bickel and Masashi,Sugiyama",
   title	 = "Direct Density Ratio Estimation for Large-scale Covariate Shift Adaptation",
   journal	 = "情報処理学会論文誌",
   year 	 = "2009",
   volume	 = "50",
   number	 = "4",
   pages	 = "1347--1364",
   month	 = "apr"
}