Van Gogh painting

[David Brooks]

This is my first posting so hopefully I won't be violating any protocols I'm
unfamiliar with. In any event, I have a quick question:

In a few of the Dune books (especially Chapterhouse Dune) a Vincent Van Gogh
painting is mentioned. The painting is called "Cottages at Cordeville" in the
books (usually listed as "Thatched Cottages at Cordeville" in any Van Gogh
reference materials) and is mentioned on a number of occasions.

I'd like to pin down exactly where all references to this Van Gogh painting
appear. Can anyone pass along page numbers or would like to share their
opinion about the significance of the Van Gogh painting in the books.

Thanks very much.