Clifford's sarcastic remark to Halley Reed that he loves Lester like a brother; David Greenglass refers to the fact David Greenglass was the brother of executed atomic spy Ethel Rosenberg and that his testimony at their trial help convict her and her husband Julius.
Lester is based on Larry Gelbart, whom both Woody Allen and Alan Alda worked with and reportedly disliked because of his despotic ways. Lester's various comments such as "Comedy is tragedy plus time" and "If it bends, it's funny; if it breaks, it's not funny" were actual Gelbart quotes. In spite of this reputed dislike for Gelbart, Allen called him "the best comedy writer that I ever knew and one of the best guys" in a statement shortly following Gelbart's death, and Alda said, "Larry's genius for writing changed my life because I got to speak his lines -- lines that were so good they'll be with us for a long, long time; but his other genius -- his immense talent for being good company -- is a light that's gone out and we're all sitting here in the dark." (from the Los Angeles Times obituary)
When Judah decides to have Delores killed, he only dials seven digits on the phone calling his brother, Jack. Judah lives in Connecticut and Jack lives in New York, so he would have to dial at least 10 digits to call him.
(at around 1h 30 mins) While they are celebrating at the wedding party the theme "Crazy Rhythm" is been played by the jazz orchestra, a muted trumpet can be heard but the trumpet player isn't using one.