Kim Hwang Su, an honorary professor at Kyongsong University of south Korea, on November 7 refuted the "prime minister's" assertion that warship Cheonan was sunk by the "north" should be included in the history textbooks.

On November 4, Dr. Yang Phan Sok of Manitoba University in Canada, who disclosed at the time of investigation that the adsorption substance which the south Korean authorities produced as convincing evidence proving the warship was sunk by explosion, expressed his opinion refuting the reckless remarks of the "prime minister".