http://news.livedoor.com/article/detail/13022858/?p=1

http://www.nikkei.com/article/DGKKZO16056920V00C17A5EA1000/

https://news.biglobe.ne.jp/trend/0507/bdc_170507_3086392953.html

https://headlines.yahoo.co.jp/hl?a=20170506-00000515-san-bus_all

https://headlines.yahoo.co.jp/hl?a=20170501-00000024-khks-soci&p=1