1. Lapin L (1990) Probability and statistics for modern engineering, 2nd edn. PWS-KENT, Boston. Chap 17, p 690
2. Manoukian EB (1986) Modern concepts and theorems of mathematical statistics. Springer, New York. Sect 3.2.1, p 111
3. Walpole RE, Myers RH, Myers SL, Ye K (2002) Probability and statistics for engineers and scientists, 7th edn. Prentice Hall, Upper Saddle River. Sect 6.10, p 172
4. Miller IR, Freund JE, Johnson R (1990) Probability and statistics for engineers, 4th edn. Prentice Hall, Englewood Cliffs. Sect 5.5, p 547
5. Dougherty ER (1990) Probability and statistics for the engineering, computing and physical sciences. Prentice Hall, Englewood Cliffs. Sect 4.8, p 190