1. Chow S-C, Chang M (2006) Adaptive design methods in clinical trials. Chapman & Hall/CRC, Boca Raton
2. Committee for Medicinal Products for Human Use (CHMP) (2006) Guideline on clinical trials in small populations (CHMP/EWP/83561/2005). European Medicines Agency, London
3. Cook TD, DeMets DL (2008) Introduction to statistical methods for clinical trials. Chapman & Hall/CRC, Boca Raton
4. Cytel Inc. (2005) StatXact® 7 PROCs For SAS® Users. Statistical Software for Exact Nonparametric Inference, User Manual. Cytel Statistical Software & Services, Cambridge
5. Dahmen G, Ziegler A (2004) Generalized estimating equations in controlled clinical trials: hypotheses testing. Biometr J 46(2):214–232