Exponential sums reference

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Looking for reference on exponential sums, in particular Jacobi, Gauss, Kloosterman and Ramanujan sums. The books mentioned in https://mathoverflow.net/questions/65429/exponential-sums-for-beginner are at a higher level than I understand, however I have read Tom Apostols analytic number theory book, so I would like a reference at that level or above.