1. Hillier, F. S. and Lieberman, G. J. 1990.Introduction to Operations Research,, 5th ed., 520New York: McGraw-Hill.
2. Mood, A. M., Graybill, F. A. and Boes, D. C. 1974.Introduction to the Theory of Statistics, 389–393. New York: McGraw-Hill.
3. Prediction Intervals for Some Discrete Distributions
4. Watson, C. J., Billingsley, P., Croft, J. C. and Huntsberger, D. V. 1993.Statistics for Management and Economics,, 5th ed., 354Boston: Allyn and Bacon.