Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Kamigaito Hidetaka and Watanabe Taro and Takamura Hiroya and Okumura Manabu and Sumita Eiichiro,Unsupervised Word Alignment Using Frequency Constraint in Posterior Regularized EM,Journal of Natural Language Processing,13407619,The Association for Natural Language Processing,2016,23,4,327-351,https://cir.nii.ac.jp/crid/1390282679452872832,https://doi.org/10.5715/jnlp.23.327