The Annotated Watchmen by Doug Atkinson (first color ebook reader txt) 📕

Panel 2: "Be seeing you" was a common phrase on the British TV show The Prisoner; the feel of the show fits Rorschach's paranoia well.

Panel 3: Rorschach's exit through the window and Veidt's "Have a nice day" is either a very subtle hint, or just coincidence.

Panel 4: The Gazette headline reads, "Nuclear Clock Stands at Five to Twelve, Warn Experts;" below it, "Geneva Talks: U.S. Refuses to Discuss Dr. Manhattan." (See the beginning of the annotation for an explanation of the nuclear clock. Five to twelve is fairly close; the closest it's been in our world is 3 to twelve, during the Cuban Missile Crisis.) The Egyptian-style pen holder fits into Veidt's Egypt obsession.

Page 19, panel 1: "Rockefeller Military Research Center, Founded 1981." The symbol on the left of the sign bears a striking resemblance to Superman's chest logo as it originally appeared.

Either Rorschach's watch is wrong, or the Veidt tow