These two links may have appeared today. It is the first time I remember noticing them. FamilySearch has been working with WorldCat (OCLC) for perhaps a year or two from what they've been saying in the past. This is the first noticable trace of this agreement I have noticed in the catalog.
I understand that FamilySearch Catalog items should be showing up in WorldCat.org at some point. Archive Grid is part of the same website.
Please don't overlook these two sources. The largest genealogical organization in the world (FamilySearch) has put prominent links here because they are extremely valuable catalogs. Almost any book has an entry in this catalog. I just helped a patron in our Family History Center find the location of a rare family history by showing him how to use WorldCat a couple weeks ago.