Book subjects

I see you've been adding a lot of books and stories to different subjects, with is terrific. I've noticed a couple instances where an entire series is linked in, though.  This is a bit of a problem because the series then gets typed as a "written work", which isn't correct -- a series (as defined in the schema, anyway) is a collection of written works, but isn't treated as one itself. I've de-typed the ones I've found, and added some help text to (hopefully) make this clearer.