You can refer to both Carl hamacher and William Stallings. For pipelining Carl hamacher is the best(according to me). For hazards portion, if the confusion remains, just go through the William Stallings, as you already have read the concepts from hamacher, it won't take much time. What I believe is if you want to have a crystal clear concept, just try to make it from wherever possible, from one book or other. Also, just go through the exercise problems of both the books once. You feel good after solving those. It might be possible that you would get stuck in some questions, if that is the case, try to solve it on GO, if solved then alright.. otherwise skip.
One thing more... There is a "What to read series by Bikram Ballav" PDF on the gate cse site, I guess. Just go through it whenever you find it difficult to decide what to read from where. It's good.
