North Korea needs more tests for nuclear missile: U.S. expert

 Reuters) - North Korea would need to carry out at least one more atomic test in order to develop a nuclear missile, a prominent U.S. scientist who has often visited the isolated Asian state said on Thursday.

http://www.reuters.com/article/2013/04/18/us-korea-north-hecker-idUSBRE93H0QK20130418