Not sure about the book, but it's in the video The Great Zapruder Film Hoax (1998) by Jack White.
34:01 [WHITE] Well, what does the Z film miss during the break between frames 132 and 133? The third lead motorcycle, the Curry/Decker lead car approaching on Houston, turning the corner and leaving the Zapruder field of view, the limo and motorcycles approaching, turning the corner in an erratic manner and entering Zapruder's field of view and reaching the location of frame 133. None of these things are seen in the present Z film. But Zapruder said that he filmed the limo turning the corner. You will learn that he was correct. Frames are missing between frames 132 and 133.
From Martin Shackelford's review "The Great Zapruder Film Hoax" Rings Very Hollow:
Jack refers to Zapruder's Warren Commission testimony, but Zapruder didn't tell the Warren Commission that he filmed the limousine turning the corner. He said: "I started shooting--when the motorcade started coming in, I believe I started and wanted to get it coming in from Houston Street." (7H571). Nowhere is he any more specific, and as the film of the limousine begins, it is "coming in from Houston Street." Later (7H573), he is shown frame 185, and says: "Yes, that--there is Elm Street there--this is a corner." And "Yes. This is where he came in from Houston Street and turned there." He is clearly pointing out the corner in the image, not saying he filmed the turn.