There is a book called Solved CSS papers Guide by Dogar publishers. I can't recall exact name. And then there are books like 20 questions on every subject, by jahangir publishers. In it they have assembled important questions from past papers. And then there is to the point series of jahangir publishers. But I think that still there is enough time. You can prepare all subjects easily. It's better to use internet or any other resource for preparation with these solved paper books. And you can find solved mcqs for various subjects at this forum. Just search through different sections of forum regarding compulsory and optional subjects.

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