1. An introducijon to medical stanistics;Bland, J.M.I.,1987
2. Clizical trials;Pocock, S.J.,1983
3. How large a sample?;Altman, D.G.,1982
4. Statistical methods Jor rates and proportions;Fleiss, J.L.,1981
5. Statistical tables Jor the design and analysis of clinical trials;Machin, D.; Ml, Campbell,1987