http://feel-japan.net/?p=6929
https://www.bloomberg.co.jp/news/articles/2018-08-20/PDQSJY6JTSE801
https://mainichi.jp/articles/20180819/k00/00e/030/151000c
https://www.zakzak.co.jp/smp/eco/news/180818/eco1808180002-s1.html
http://news.livedoor.com/lite/article_detail/14885186/