http://jp.wsj.com/articles/SB10421733196172483684504581435110635935714

http://headlines.yahoo.co.jp/hl?a=20151230-00010003-doshin-pol

http://www.utp.or.jp/shohyou/2015/12/18/nikkeisanngyo_32378/

http://www.msn.com/ja-jp/news/opinion/%E7%84%A1%E8%81%B7%E3%81%AE%E5%BC%81%E8%AD%B7%E5%A3%AB%E3%81%8C%E5%A2%97%E3%81%88%E3%81%A6%E3%81%84%E3%82%8B%EF%BC%9F/ar-BBo3eeH?ocid=NAMDHP#page=2

http://blog.goo.ne.jp/j-j-n/e/9e4940c8bedbec00145f81713f0d7971