Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) ICHISAWA Yutaka,A Study on the History of Educational Practices for Children with Intellectual Disabilities in Hokkaido:Special Education for Underachievers and Mentally Retarded Children prior to World War Ⅱ,北海道大学大学院教育学研究科紀要,13457543,北海道大学大学院,2003-06,90,,71-143,https://cir.nii.ac.jp/crid/1390290699771053440,https://doi.org/10.14943/b.edu.90.71