The sources exist in Musings, but they are akin to creation myths and the characters do not associate them with themselves. It's possible that in the human world, however, someone might make the connection (if they're close enough to their source.)
Everything in Musings mirrors exactly, down to the books and politicians. The main difference is that there aren't any powers in Musings, and the Creations do not know they come from the imagination of humanity precisely. Basically, written items are their Bibles.