著者名,論文名,雑誌名,ISSN,出版者名,出版日付,巻,号,ページ,URL,URL(DOI) Akiyo HIRAI,The Effects of Study Abroad Duration and Predeparture Proficiency on the L2 Proficiency of Japanese University Students: A Meta-Analysis Approach,日本言語テスト学会誌,21895341,日本言語テスト学会,2018,21,0,102-123,https://cir.nii.ac.jp/crid/1390564238056885120,https://doi.org/10.20622/jltajournal.21.0_102