I am looking for a recommendation on books with problems similar to pgre problems. I already have Halliday Resnick, Schaum's 3000 solved problems, and the new Conquering Physics GRE book by Yoni Khan, and have pretty much gone through them all in detail, so I feel I understand all of the necessary concepts well. However, I feel that I need to work on my speed in solving a problem, so I basically want another couple of books with problems on the same level as pgre. Something on the level of Schaum's, but preferably a bit harder (but not as hard as prelim/qualifier questions..i need problems i can solve in 2-3 min) will be superb. Any ideas? Thanks!