Required:
Murray and A War to Be Won, pp. 484-526.

Douglas J. MacEachin, The Final Months of the War with Japan: Signals Intelligence, U.S. Invaison Planning, and the A-Bomb Decision (Washington, D.C.: Central Intelligence Agency, Center for the Study of Intelligence, 1998), pp. 1-13, 14-26, 27-38 (pdf).

Sadao Asada, "The Shock of the Atomic Bomb and Japan's Decision to Surrender--A Reconsideration," Pacific Historical Review, November 1998, vol. 67, (4), pp 477-95, 496-512 (pdf).

Suggested:
Gar Alperovitz, The Decision to Use the Atomic Bomb and the Architecture of an American Myth (New York: A.A. Knopf, 1995).

Herbert P. Bix, Hirohito and the Making of Modern Japan (London: Duckworth, 2000), pp. 487-530.

Richard Rhodes, The Making of the Atomic Bomb (New York: Simon & Schuster, 1986).

J. Samuel Walker, Prompt and Utter Destruction: Truman and the Use of Atomic Bombs Against Japan (Chapel Hill: University of North Carolina Press, 1997).

Martin Sherwin, A World Destroyed: The Atomic Bomb and the Grand Alliance (New York: Knopf, 1975).

"Heisenberg in Copenhagen: An Exchange," New York Review of Books, February 8, 2001 (.pdf)