References
- Johnson , N. L. , Kotz , S. and Kemp , A. W. 1992 . Univariate Discrete Distributions, , 2nd ed. , New York : John Wiley .
- Kendall , M. G. , Stuart , A. and Ord , J. K. 1987 . Kendall's Advanced Theory of Statistics , London : Griffin .
- Mood , A. F. , Graybill , F. A. and Boes , D. C. 1973 . Introduction to the Theory of Statistics, , 3rd ed. , New York : McGraw-Hill .