There is an Easter Egg at 34:17 during the film where the Store cashier is seen reading "Season of the Witch" by Christopher Knight. Christopher Knight is the Author of "Bestseller" as well which the film is based upon.
This is the first film adaptation of any novel by Christopher Knight.
Christopher Knight (Actually a 'pseudoname' for the author's real name which is Jonathan Rand) has a cameo in the film. He plays the Attorney for Gerald Morgan during the interrogation scene.
Christopher Knight (Wright) also writes children's books under the pen name Johnathan Rand.