D. F. Andrews & A. M. Herzberg (1985),
Data: A Collection of Problems from Many Fields for the Student
and Research Worker.
Springer-Verlag, New York, NY.
R. A. Fisher (1925),
Statistical Methods for Research Workers.
Oliver & Boyd, London.
L. von Bortkiewicz (1898),
Das Gesetz der kleinen Zahlen.
Teubner, Leipzig.
M. Friendly (2000),
Visualizing Categorical Data.
SAS Institute, Cary, NC.