http://diamond.jp/articles/-/10553
http://www.asahi.com/health/news/TKY201012300271.html
http://www.yomiuri.co.jp/politics/news/20101231-OYT1T00020.htm?from=main6
http://www.yomiuri.co.jp/national/news/20101231-OYT1T00034.htm?from=top
http://www.nhk.or.jp/news/html/20101230/k10013140001000.html
http://www.nhk.or.jp/news/html/20101230/k10013139901000.html
http://www.nhk.or.jp/news/html/20101230/k10013144651000.html