John Schilling, "A Revised Assessment of the North Korean KN-08 ICBM," Science & Global Security, 21, no. 3, (2013): 210-236.
The mobile ICBM displayed in Pyongyang last April is analyzed in light of North Korea's known and reasonably suspected capabilities in the field, particularly those demonstrated in the recent and successful Unha-3 launch. Several possible configurations for the KN-08 missile are given, and performance estimates are presented. While the displayed missiles are clearly mock-ups, they are consistent with an ongoing development program for a missile with limited intercontinental capability using only existing North Korean technology. The lack of flight testing strongly suggests that operational deployment is still months or years in the future, though an initial test could come at any time. Even with a successful test program, any such North Korean ICBM would likely be unreliable, limited in mobility and performance, and available only in small numbers