Red hat RHCDS self-study recommendation

I will soon pass the red hat EX300 and I would like to keep studying red hat for the RHCDS. I'm looking at the available books needed exams and I can't seems to find a books specifically on the required exams topic. Is there resource available for these exams (EX318/EX401/EX436)? I'm afraid of under/over study just by looking at the exam objectives.

Edit: Do anyone did the exam only by looking at the objectives? This seems to be a big bet considering the exam price, still cheaper than the course, but still steep.