Personally, I think Li Yongle is better. Mathematics can buy real questions over the years. There is a book compiled by Wu Zhongxiang, which is good and detailed. They are all real problem analysis over the years. I don't think it necessary to read many math reference books. It is good to do the real questions 3-5 times over the years. You can make a simulation prediction before the exam. You can order from Joyo or Dangdang. They are all genuine books, which are cheaper than bookstores, to pay the freight. It's really good. In short, no matter which subject, reference books are not too easy. 1-2 each subject is enough, and the schedule will not be very tight. I suggest reading more real questions. I wish you success!