J. K. Lindsey (1995),
Analysis of Frequency and Count Data.
Oxford University Press, Oxford, UK. R. R. Sokal & F. J. Rohlf (1969),
Biometry. The Principles and Practice of Statistics.
W. H. Freeman, San Francisco, CA.
M. Friendly (2000),
Visualizing Categorical Data.
SAS Institute, Cary, NC.