Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) 土井 幸治 and Doi Koji,Research trend on class collapse ―Text mining for literature titles―,西九州大学健康福祉学部紀要,2434-8775,西九州大学,2020-03-01,49,,25-31,https://cir.nii.ac.jp/crid/1390292706102031744,https://doi.org/10.20830/00000090