- "As he spoke, Brown got out of the vehicle, revealing himself in all his sci-fi spendor. He thought he must resemble Michael Rennie stepping onto Earth for the first time in The Day the Earth Stood Still."
- —From Back to the Future by George Gipe (quote, page 46)
The Day the Earth Stood Still was a 1951 black and white science-fiction movie starring Michael Rennie, which was based on a 1940 science-fiction short story called Farewell to the Master, written by Harry Bates.
Emmett Brown had seen the movie at some point, presumably in 1951 at either the Town Theater or the Essex Theater in Hill Valley. When Doc, clad in his radiation suit, got out of the DeLorean time machine on meeting Marty McFly at Twin Pines Mall on October 26, 1985, he remembered the scene where Rennie's character, the humanoid alien Klaatu, first stepped from his flying saucer onto Earth.
- Back to the Future novelization (Mentioned only)