The US and South Korean navies took to the seas Monday with a message for North Korea: Think twice before you threaten us.
원문출처 : http://www.cnn.com/2016/09/25/asia/north-korea-submarine-technology/index.html
원문출처 : http://www.cnn.com/2016/09/25/asia/north-korea-submarine-technology/index.html