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伊江島 城山(タッチュー) [Iejima Gusuku (Tatchū)] (in Japanese). Okinawa Joho IMA. 2006. Retrieved Jan 6, 2012.
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城山(タッチュー)の情報 [Information on Mount Gusuku (Tatchū)] (in Japanese). Ie, Okinawa Prefecture, Japan: Village of Ie. 2007. Retrieved Jan 6, 2013.
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"伊江島" [Iejima]. Nihon Rekishi Chimei Taikei (in Japanese). Tokyo: Shogakukan. 2012. OCLC173191044. Archived from the original on 2007-08-25. Retrieved 2012-12-07.
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"伊江島" [Iejima]. Nihon Rekishi Chimei Taikei (in Japanese). Tokyo: Shogakukan. 2012. OCLC173191044. Archived from the original on 2007-08-25. Retrieved 2012-12-07.