Book Issues

[Dominick]

I have some questions/observations about a book. First, this book:

https://www.goodreads.com/book/show/1...

and this book:

https://www.goodreads.com/book/show/6...

Are actually both the same book, Ace double D-407, including both Poul Anderson's We Claim These Stars! and Robert Silverberg's The Planet Killers. They should therefore be combined, I assume.

However, what is (is or is there) policy re: things like Ace doubles, which are essentially two books in one? Presumably, one should be able to find either or both of the texts included in such a book by searching for one or the other, but in this instance, the Silverberg half of the book is not listed among the alternate editions of The Planet Killers. Should such books be listed so both authors and both titles are searchable separately? Should there be separate entries for each "half," with separate cover images? BTW, here is a link to my scan of the cover for the Silverberg half:

http://s296.photobucket.com/user/dgra...

Regardless of how it/they should be listed, there is information missing. There is no page count info provided. For the Anderson half, the page count is 125. for the Silverberg half, it is 131. The total, therefore, is 256.

Thanks.