@book{oai:nichibun.repo.nii.ac.jp:00005298,
 author = {SERAFIM,  Leon A.},
 month = {Dec},
 publisher = {国際日本文化研究センター, International Research Center for Japanese Studies},
 title = {When and from Where did the Japonic Language Enter the Ryukyus?-A Critical Comparison of Language, Archaeology, and History},
 volume = {31},
 year = {2003}
}