http://www.nikkei-science.com/201302_050.html http://www.nikkei-science.com/page/sci_book/bessatu/51197.html

http://headlines.yahoo.co.jp/hl?a=20140220-00000210-jij-n_ame

http://news.goo.ne.jp/article/mainichi/nation/20140221k0000m040124000c.html

http://www.hokkaido-np.co.jp/news/donai/520885.html

http://mainichi.jp/select/news/20140221k0000m040096000c.html

http://headlines.yahoo.co.jp/hl?a=20140221-00010009-minyu-l07