Batman The Dark Knight Returns & Absolute Dark Knight... as far as i understand, the only difference between these two is the resized pages, and the extras... but i think (THINK) they are the same.
So, anyone who is more familiar with this work, can you tell me if i should combine them?

Nope. Not the same. Note how one is twice as many pages as the other. From the description of Absolute Dark Knight:

THE DARK KNIGHT RETURNS set the world on fire. 15 years later, Miller's sequel, THE DARK KNIGHT STRIKES AGAIN, further redefined the boundaries of the superhero genre.

Now, both of these comics masterpieces are collected in one giant-sized slipcase edition for the first time ever.

Ya, but look at this

http://www.goodreads.com/work/editions/4...

Both, absolute and no absolute editions are considered editions of the same book, althought the absolute has a lot of material the other one doesn't.

There's a fundamental difference. The Absolute Dark Knight is an omnibus of two different collections. The different versions of the Watchmen are (I think) more like bonus material.

Rodrigo, the difference isn't that it's the "Absolute" edition, the difference is that Batman The Dark Knight Returns is one book and Batman The Dark Knight Strikes Again is it's sequel.

In this case, the "Absolute" edition is an omnibus of the two separate books, with some additional material, so it should not be combined with either of the novels it contains.

In the link you gave above, "Watchmen" is only one book, there is no sequel. The "Absolute" edition has more material, yes, and should still be combined with all other editions of "Watchmen" because the core of each book is the same book.

Ok, now i've it very clear, thank you guys, i didn't know about the sequel....