http://www3.nhk.or.jp/news/html/20151221/k10010348781000.html

http://www.nikkei-science.com/201602_092.html

http://suguyare.hatenablog.com/entry/20151223/1450854389

http://headlines.yahoo.co.jp/hl?a=20151221-00000578-san-soci

http://www.tokyo-np.co.jp/article/national/list/201512/CK2015122202000126.html