Complex sentence: The story is based upon the 1956 Newbery Honor-winning book "Old Yeller" by Fred Gipson, who also co-wrote the screenplay with William Tunberg.
Split into simpler sentences: The story is based upon the 1956 Newbery Honor-winning book "Old Yeller" by Fred Gipson. Gipson also co-wrote the screenplay with William Tunberg.