Fried, Robert C. "What If Hitler Got the Bomb? (1944)."
Divergence: 1942 CE
What if: After Heisenberg produced a laboratory chain reaction, Germany went on to produce A-bombs in early 1944, dropping them on London and Leningrad in May.
Comments: An essay arguing how unlikely such a course of events was, and how the Nazis would still have lost the war due to superior Allied air power.
Published: In What If? Explorations in Social-Science Fiction (ed. Nelson W. Polsby), q.v.