@techreport{weko_32570_1,
   author	 = "半田,恵一",
   title	 = "Topes　of　Oriented　Matroids　and　Related　Structures",
   year 	 = "1991",
   institution	 = "（株）東芝システム・ソフトウェア技術研究所",
   number	 = "79(1991-AL-023)",
   month	 = "sep"
}