General GMAT Questions and Strategies | Re: Which book(s) should I use?

Hey guys I want to take the GMAT in May and in few weeks I want to start with my preparations. My target is at least 680-700! Which books are useful to reach this target? I´m planning to buy the official guide, but which other books would you guys recommend for an optimal preparation? I´m planning to study 8-10 weeks (full time).

Thanks in advance!