https://www.atmarkit.co.jp/ait/spv/1903/20/news047.html
https://www.itmedia.co.jp/news/spv/1903/20/news092_0.html
https://www.bloomberg.co.jp/news/articles/2019-03-19/POMR3QSYF01S01
https://headlines.yahoo.co.jp/article?a=20190320-00197242-diamond-bus_all&p=3