<p>I think the books that anyone would recommend is the Art of Problem Solving books, you can find them here - [Art</a> of Problem Solving](<a href=“http://www.artofproblemsolving.com%5DArt”>http://www.artofproblemsolving.com). They also have classes, and even if you don’t want to spend the money on books or classes, there’s a wiki, past tests, contests, and a messageboard you can use to prepare. So yea, there’s a lot of stuff you can find there.</p>