@article{weko_13417_1,
   author	 = "Ning,Zhong and Setsuo,Ohsuga",
   title	 = "On Information of Logical Expression and Knowledge Refinement",
   journal	 = "情報処理学会論文誌",
   year 	 = "1997",
   volume	 = "38",
   number	 = "4",
   pages	 = "687--697",
   month	 = "apr"
}