@article{weko_186820_1,
   author	 = "Yo,Ehara and Issei,Sato and Hidekazu,Oiwa and Hiroshi,Nakagawa",
   title	 = "Mining Words in the Minds of Second Language Learners for Learner-specific Word Difficulty",
   journal	 = "情報処理学会論文誌",
   year 	 = "2018",
   volume	 = "59",
   number	 = "3",
   month	 = "mar"
}