1. D. G. Cantor, R. R. Phelps (1965):An elementary interpolation theorem. Proc. Amer. Math. Soc.,16:523–525.
2. H. G. Eggleston (1958): Convexity. Cambridge Tracts in Mathematics and Mathematical Physics, no. 47. Cambridge: Cambridge University Press.
3. C. T. Mullis, R. A. Roberts (1986): Digital Signal Processing. Reading, MA: Addison-Wesley, Section 6.7.
4. W. D. Stanley, G. R. Dougherty, R. Dougherty (1984): Digital Signal Processing. Reston, VA: Reston.
5. S. A. Tretter (1976): Introduction to Discrete-Time Signal Processing. New York: Wiley.