1. A. W. Naylor and G. R. Sell.Linear Operator Theory in Engineering and Science2nd ed., Springer-Verlag, New York, 1982.
2. I. C. Gohberg and M. G. Krein.Introduction to the Theory of Linear Nonselfadjoint OperatorsAmer. Math. Soc., Providence, RI, 1969.
3. L.E.FranksSignal Theory.Prentice Hall, Englewood Cliffs, NJ, 1969.
4. T. Kailath.Linear Systems. Prentice Hall, Englewood Cliffs, NJ, 1980.
5. L. R. Rabiner and R. W. Schafer.Digital Processing of Speech SignalsPrentice Hall, Englewood Cliffs, NJ, 1978.