Accidental Re-upload. The first book from this series is categorized as Doujinshi. The original upload of this book is categorized as Artist CG and I had that category disabled by default. Rookie Mistake... :P Not sure which one is the right answer since this was released at an event.
Well shoot... The other book scans from this artist were tagged as Doujinshi, The one you linked was Artist CG and I have that category disabled by default. Rookie Mistake :P
@HimegamiF: The category for artbooks was changed a few months ago from Doujinshi to Artist CG, so Artist CG is the correct category now. https://ehwiki.org/wiki/artbook