http://gigazine.net/news/20130905-sleep-boost-brain-cell/

http://zasshi.news.yahoo.co.jp/article?a=20130906-00500007-sspa-soci

http://sankei.jp.msn.com/affairs/news/130905/trl13090519380008-n1.htm

http://headlines.yahoo.co.jp/hl?a=20130905-00001165-yom-soci

http://headlines.yahoo.co.jp/hl?a=20130905-00000117-jij-soci