Complex sentence: This is the only work involving Parker and Stone that was neither written, directed, nor produced by them, although Zucker himself has said Parker and Stone contributed innumerable suggestions for the film, most of which were used.
Split into simpler sentences: This is the only work involving Parker and Stone that was neither written, directed, nor produced by them. Though Zucker himself has said Parker and Stone contributed innumerable suggestions for the film, most of which were used.