Hi -
As noted above, the publisher for the Diomin Campaign Setting is Otherworld Creations. The name of the product is actually just called "Diomin".
Also, you may want to change the wording of your category called "Prestige Classes - Assassin" because several of the products listed there (such as Green Ronin's Assassin's Handbook and I think also Mongoose's Power Classes: Assassin) present alternative Assassin core classes. I would personally just make the category more general and call it "Assassins".
Have you thought about adding categories for the various races? The reason I ask is that, while a book like "Heroes of High Favor - Dwarves" is really geared toward the fighter favored classes of Dwarves (and is therefore useful for all fighters), a book like Green Ronin's "Hammer & Helm" is not so much a resource for fighters as it is a general all around resource for Dwarf characters and culture. I have, and like, both books, but I'm not sure that I would list "Hammer & Helm" under the "Fighter Class" resource books.
Lastly, I think that there are enough resources available for you to add an "Alternative Classes: Samurai" category:
* Oriental Adventures (WotC)
* Rokugan (AEG)
* Way of the Samurai (AEG)
* Hunt: Rise of Evil (Mystic Eye Games)
Okay, one more "lastly": is "Encyclopedia Arcane: Divination" available yet? I see it on Mongoose's site but I don't see any info. about it here on ENWorld in the Reviews section. Just curious because I see you have it listed under the Specialist School Books category.