A. V. Oppenheim's A.S. Willsky's with S. Hamid's Signals(Signals and Systems (2nd Edition) [Hardcover])(1996)

This authoritative book, highly regarded for its intellectual quality and contributions provides a solid foundation and life-long reference for anyone studying the most important methods of modern signal and system analysis. The major changes of the revision are reorganization of chapter material and the addition of a much wider range of difficulties.