Chang, M. N. (1989). “Confidence Intervals for a Normal Mean Following a Group Sequential Test.” Biometrics 45:247–254.
Chang, M. N., Gould, A. L., and Snapinn, S. M. (1995). “p-Values for Group Sequential Testing.” Biometrika 82:650–654.
Chow, S.-C., and Liu, J.-P. (1998). Design and Analysis of Clinical Trials: Concept and Methodologies. New York: John Wiley & Sons.
Chow, S.-C., Shao, J., and Wang, H. (2003). Sample Size Calculations in Clinical Research. Boca Raton, FL: CRC Press.
Cox, D. R. (1972). “Regression Models and Life Tables.” Journal of the Royal Statistical Society, Series B 20:187–220. With discussion.
DeMets, D. L., Furberg, C. D., and Friedman, L. M. (2006). Data Monitoring in Clinical Trials. New York: Springer.
Dmitrienko, A., Molenberghs, G., Chuang-Stein, C., and Offen, W. (2005). Analysis of Clinical Trials Using SAS: A Practical Guide. Cary, NC: SAS Institute Inc.
Ellenberg, S. S., Fleming, T. R., and DeMets, D. L. (2003). Data Monitoring Committees in Clinical Trials. New York: John Wiley & Sons.
Emerson, S. S. (1996). “Statistical Packages for Group Sequential Methods.” American Statistician 50:183–192.
Emerson, S. S., and Fleming, T. R. (1989). “Symmetric Group Sequential Designs.” Biometrics 45:905–923.
Emerson, S. S., and Fleming, T. R. (1990). “Parameter Estimation Following Group Sequential Hypothesis Testing.” Biometrika 77:875–892.
Fairbanks, K., and Madsen, R. (1982). “p-Values for Tests Using a Repeated Significance Test Design.” Biometrika 69:69–74.
Food and Drug Administration (1998). “E9: Statistical Principles for Clinical Trials.” Federal Register 63:49583–49598.
Herson, J. (1979). “Predictive Probability Early Termination for Phase II Clinical Trials.” Biometrics 35:775–783.
Hwang, I. K., Shih, W. J., and DeCani, J. S. (1990). “Group Sequential Designs Using a Family of Type I Error Probability Spending Functions.” Statistics in Medicine 9:1439–1445.
Jennison, C., and Turnbull, B. W. (2000). Group Sequential Methods with Applications to Clinical Trials. New York: Chapman & Hall.
Kim, K., and Tsiatis, A. A. (1990). “Study Duration for Clinical Trials with Survival Response and Early Stopping Rule.” Biometrics 46:81–92.
Kittelson, J. M., and Emerson, S. S. (1999). “A Unifying Family of Group Sequential Test Designs.” Biometrics 55:874–882.
Lan, K. K. G., and DeMets, D. L. (1983). “Discrete Sequential Boundaries for Clinical Trials.” Biometrika 70:659–663.
Lan, K. K. G., Lachin, J. M., and Bautista, O. (2003). “Over-ruling a Group Sequential Boundary: A Stopping Rule versus a Guideline.” Statistics in Medicine 22:3347–3355.
Lan, K. K. G., Simon, R., and Halperin, M. (1982). “Stochastically Curtailed Tests in Long-Term Clinical Trials.” Sequential Analysis 1:207–219.
McCullagh, P., and Nelder, J. A. (1989). Generalized Linear Models. 2nd ed. London: Chapman & Hall.
Mehta, C. R., and Tsiatis, A. A. (2001). “Flexible Sample Size Considerations under Information Based Interim Monitoring.” Drug Information Journal 35:1095–1112.
O’Brien, P. C., and Fleming, T. R. (1979). “A Multiple Testing Procedure for Clinical Trials.” Biometrics 35:549–556.
Proschan, M. A., Lan, K. K. G., and Wittes, J. T. (2006). Statistical Monitoring of Clinical Trials. New York: Springer.
Rosner, G. L., and Tsiatis, A. A. (1988). “Exact Confidence Intervals Following a Group Sequential Trial: A Comparison of Methods.” Biometrika 75:723–729.
Rudser, K. D., and Emerson, S. S. (2007). “Implementing Type I and Type II Error Spending for Two-Sided Group Sequential Designs.” Contemporary Clinical Trials 29:351–358.
Scharfstein, D. O., and Tsiatis, A. A. (1998). “The Use of Simulation and Bootstrap in Information-Based Group Sequential Studies.” Statistics in Medicine 17:75–87.
Tsiatis, A. A., and Mehta, C. R. (2003). “On the Inefficiency of the Adaptive Design for Monitoring Clinical Trials.” Biometrika 90:367–378.
Tsiatis, A. A., Rosner, G. L., and Mehta, C. R. (1984). “Exact Confidence Intervals Following a Group Sequential Test.” Biometrics 40:797–803.
Ware, J. H., Muller, J. E., and Braunwald, E. (1985). “The Futility Index: An Approach to the Cost-Effective Termination of Randomized Clinical Trials.” American Journal of Medicine 78:635–643.
Whitehead, J. (1997). The Design and Analysis of Sequential Clinical Trials. Rev. 2nd ed. Chichester, UK: John Wiley & Sons.
Zhu, L., Ni, L., and Yao, B. (2011). “Group Sequential Methods and Software Applications.” American Statistician 65:127–135.