Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Hirayama Takuji and Fukuda Makoto and Hirakawa Morihiko,Seasonal Change of Vocalization of the Okinawa Rail (Gallirallus okinawae),Journal of the Yamashina Institute for Ornithology,13485032,Yamashina Institute for Ornitology,2013,45,1,1-8,https://cir.nii.ac.jp/crid/1390282680197991040,https://doi.org/10.3312/jyio.45.1