From New Hope Arts, this listing of an exhibit, Cartoon Limbo, featuring rejected work by some of the great cartoonists, including James Thurber, Chester Gould (“Dick Tracey”), Dr. Suess, and Charles Schulz.
From Phillyburbs.com, April 1, 2011, this related article, “Seal of Disapproval,” about the cartoonist behind the exhibit, Lewis Matheney.