Update at 20:00 KST: This article has been amended to include a response from Cornell University Press, Armstrong’s publisher

Charles K Armstrong, a long-time Korea studies professor at Columbia University, has been found to have plagiarized sources used in his critically-lauded 2013 book “Tyranny of the Weak” and will retire, his employers said this week.

In a statement, Media Relations Director at Columbia University Caroline Adelman said that an internal investigation had determined that Armstrong had breached the university’s research standards.

“Consistent with Columbia’s policies and procedures governing research misconduct, the University has determined that Professor Charles K. Armstrong committed