References
- Scott , A. J. and Seber , G. A. F. 1983 . “Difference of Proportions From the Same Survey” . The American Statistician , 37 : 319 – 320 .
- Siegel , S. 1956 . Nonparameteric Statistics for the Behavioral Sciences, , International Student ed. , Tokyo : McGraw-Hill Kogakusha .