I am wondering if the story on which the 2018 film Christopher Robin is based has been published anywhere, and it appears not. Its Wikipedia page states:
Christopher Robin is a 2018 American fantasy comedy-drama film directed by Marc Forster and written by Alex Ross Perry, Tom McCarthy, and Allison Schroeder, from a story by Greg Brooker and Mark Steven Johnson.
Screenplay by: Alex Ross Perry, Tom McCarthy, Allison Schroeder
Story by Greg Brooker, Mark Steven Johnson
Based on: Characters from: Disney's Winnie the Pooh, Winnie-the-Pooh books, by A. A. Milne, E. H. Shepard
However, this file I found online allegedly from Disney doesn't credit Brooker and Johnson. Wikipedia claims they are co-recipients of the Humanitas Prize together with the screenwriters. So what is the difference between "story by" and "screenplay by" (if the story does not refer to the original story)? "Based on" is easier to understand in this context.