[1] 膠州湾 - Wikipedia (2/2/2019, 5:43:33 AM) https://ja.wikipedia.org/wiki/%E8%86%A0%E5%B7%9E%E6%B9%BE
[2] 膠州湾租借地 - Wikipedia (1/21/2019, 4:39:34 PM) https://ja.wikipedia.org/wiki/%E8%86%A0%E5%B7%9E%E6%B9%BE%E7%A7%9F%E5%80%9F%E5%9C%B0
[3] チヤオチョウ(膠州)(地図)/(Kiaochau.) (2/4/2019, 8:26:16 AM) http://db.nichibun.ac.jp/ja/d/GAI/info/GM123/item/010/
Google search: Kiautschou