Thanks for the link to Harold Hering's article. I just read it, as well as the one on Stanislav Petrov.

Vasili Arkhipov's Wikipedia article is also worth reading. Although most Russian nuclear submarines required only the captain's order to launch, he was the only one of the three officers on his sub to vote against launching their nukes during the Cuban Missile Crisis. Due to his position as Flotilla commander, he was able to win the argument with the submarine's captain, who wanted to launch.