John Lasseter Q&A - Who wrote the story for Up?

John Lasseter answers a fan question about how many people wrote Up.:

Two people really wrote the story for Up, and that is Pete Docter and Bob Peterson. But there's more than that, there's the story department. ... We never let a sequence of a movie go into production until it is working fantastically. ... The storyboard artists are really intimately involved along with the screenwriters.

--Dailymotion - John Lasseter Q&A Who wrote the story for Up? - Video