1. Brown BW, Hollander M. Statistics: A Biomedical Introduction. New York: John Wiley and Sons, 1977.
2. Armitage P. Statistical Methods in Medical Research. New York: John Wiley and Sons, 1977.
3. Breslow N. Comparison of survival curves. In Buyse B, Staquet M, Sylvester R (eds). The Practice of Clinical Trials in Cancer. Oxford: Oxford University Press, 1982.
4. Altman DG. Practical Statistics for Medical Research. New York: Chapman and Hall, 1991, pp. 383–392.
5. Woolson R. Statistical Methods for the Analysis of Biomedical Data. New York: John Wiley and Sons, 1987.