You can search the library catalog (the big search bar) for the name of the artist, limiting the search to books in the Oversized section. To do this, choose "Oversized (Upper)" as the Location in the drop-down under the search bar, and choose "Books" above the search bar.
See the example (screenshot below).
As you look through the results, jot down the call numbers and notice they should all be very similar.
The books you're looking for should be very close together on the shelf.
