http://www.nikkei-science.com/201803_072.html

http://www3.nhk.or.jp/shutoken-news/20180220/0008264.html

https://twitter.com/1961kumachin/status/965496705209663489

https://headlines.yahoo.co.jp/article?a=20180219-00537847-shincho-bus_all&p=1

https://headlines.yahoo.co.jp/hl?a=20180219-00050004-yom-pol