参考 https://www.gakushuin.ac.jp/univ/geore/research/2015a/bujun-nagayasubashi.htmlhttp://www.china-qiao.com/ql07/fsql/fsql005.htmhttps://www.google.com/maps/place/%E6%B0%B8%E5%AE%89%E6%A9%8B/@41.8708315,123.9055948,850m/data=!3m1!1e3!4m6!3m5!1s0x5e2fec0798264661:0xac1e6a6d578529b7!8m2!3d41.8723238!4d123.9145877!16s%2Fg%2F11x7vdgnl?hl=ja&entry=ttu
http://www.nicovideo.jp/watch/sm42860592
