References/Notes/Attributions:
Source
Michael Friendly (2000), Visualizing Categorical Data: http://euclid.psych.yorku.ca/ftp/sas/vcd/catdata/arthrit.sas
References
G. Koch \& S. Edwards (1988), Clinical efficiency trials with categorical data. In K. E. Peace (ed.), Biopharmaceutical Statistics for Drug Development, 403–451. Marcel Dekker, New York.
M. Friendly (2000), Visualizing Categorical Data. SAS Institute, Cary, NC.