2017-10-17 ■ https://mathway.zendesk.com/hc/en-us/community/posts/115001962852-LIVE-%E6%97%A5%E6%9C%AC-U-17-vs-%E3%82%A4%E3%83%B3%E3%82%B0%E3%83%A9%E3%83%B3%E3%83%89-U-17-%E3%83%A9%E3%82%A4%E3%83%96%E3%82%B9%E3%83%88%E3%83%AA%E3%83%BC%E3%83%A0-2017