Which publisher should I choose?

Hello,

I'm writing my BA thesis on Brave New World, and I have to buy a book from which I have to put quotations, numbers of pages and so on.
My teacher told me that there are better and worse publications of BNW. Unfortunately I can't find it in my city, so I have to order it. So far I've came across "Vintage" (229 pages), "Vintage Classics" (256 pages) "BANNED BOOKS" series (200 pages), "HarperCollins" (259 pages) and "Vintage Classics" with 288 pages and introduction by Margaret Atwood.
I know it may seem trivial, but for me it's the matter of life and death.
I would really appreciate your help.