Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) BUTLER JE,Humoral immunity in root caries in an elderly population. 1,Oral Microbiol Immunol,,,1990,5,,98-107,https://cir.nii.ac.jp/crid/1570572701439086464,https://doi.org/10.1111/j.1399-302x.1990.tb00236.x