http://gendai.ismedia.jp/articles/-/51622?page=2
https://news.yahoo.co.jp/byline/tsudakenji/20180102-00080010/
https://www.bloomberg.co.jp/news/articles/2017-12-19/P153LL6S972801
https://style.nikkei.com/article/DGXMZO25043010V21C17A2000000
http://news.livedoor.com/lite/article_detail_amp/14104737/