Armitage, P., McPherson, C. K., and Rowe, B. C. (1969). “Repeated Significance Test on Accumulating Data.” Journal of the Royal Statistical Society, Series A 132:235–244.
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., and Hinkley, D. V. (1974). Theoretical Statistics. London: Chapman & Hall.
DeMets, D. L., Furberg, C. D., and Friedman, L. M. (2006). Data Monitoring in Clinical Trials. New York: Springer.
Diggle, P. J., Heagerty, P., Liang, K.-Y., and Zeger, S. L. (2002). Analysis of Longitudinal Data. 2nd ed. New York: Oxford University Press.
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.
Efron, B., and Hinkley, D. V. (1978). “Assessing the Accuracy of the Maximum Likelihood Estimator: Observed versus Expected Fisher Information.” Biometrika 65:457–483.
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., Kittelson, J. M., and Gillen, D. L. (2005). “On the Use of Stochastic Curtailment in Group Sequential Clinical Trials.” UW Biostatistics Working Paper Series, No. 243. http://www.bepress.com/uwbiostat/paper243.
Food and Drug Administration (1998). “E9: Statistical Principles for Clinical Trials.” Federal Register 63:49583–49598.
Haybittle, J. L. (1971). “Repeated Assessment of Results in Clinical Trials of Cancer Treatment.” British Journal of Radiology 44:793–797.
Hsieh, F. Y., and Lavori, P. W. (2000). “Sample-Size Calculations for the Cox Proportional Hazards Regression Model with Nonbinary Covariates.” Controlled Clinical Trials 21:552–560.
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. (1990). “Statistical Approaches to Interim Monitoring of Medical Trials: A Review and Commentary.” Statistical Science 5:299–317.
Jennison, C., and Turnbull, B. W. (2000). Group Sequential Methods with Applications to Clinical Trials. New York: Chapman & Hall.
Kalbfleisch, J. D., and Prentice, R. L. (1980). The Statistical Analysis of Failure Time Data. New York: John Wiley & Sons.
Kim, K., and DeMets, D. L. (1987). “Design and Analysis of Group Sequential Tests Based on the Type I Error Spending Rate Function.” Biometrika 74:149–154.
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.
Lachin, J. M., and Foulkes, M. A. (1986). “Evaluation of Sample Size and Power for Analyses of Survival with Allowance for Nonuniform Patient Entry, Losses to Follow-Up, Noncompliance, and Stratification.” Biometrics 42:507–519.
Lan, K. K. G., and DeMets, D. L. (1983). “Discrete Sequential Boundaries for Clinical Trials.” Biometrika 70:659–663.
Lan, K. K. G., and DeMets, D. L. (2009). “Further Comments on the Alpha-Spending Function.” Statistics in Biosciences 1:95–111.
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.
Lindgren, B. W. (1976). Statistical Theory. 3rd ed. New York: Macmillan.
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.
O’Neill, R. T. (1994). “Interim Analysis: A Regulatory Perspective on Data Monitoring and Interim Analysis.” In Statistics in the Pharmaceutical Industry, edited by C. R. Buncher, and J.-Y. Tsay, 285–290. New York: Marcel Dekker.
Pampallona, S., and Tsiatis, A. A. (1994). “Group Sequential Designs for One-Sided and Two-Sided Hypothesis Testing with Provision for Early Stopping in Favor of the Null Hypothesis.” Journal of Statistical Planning and Inference 42:19–35.
Peto, R., Pike, M. C., Armitage, P., Breslow, N. E., Cox, D. R., Howard, S. V., Mantel, N., McPherson, K., Peto, J., and Smith, P. G. (1976). “Design and Analysis of Randomized Clinical Trials Requiring Prolonged Observation of Each Patient: I. Introduction and Design.” British Journal of Cancer 34:585–612.
Pocock, S. J. (1977). “Group Sequential Methods in the Design and Analysis of Clinical Trials.” Biometrika 64:191–199.
Pocock, S. J. (1982). “Interim Analyses for Randomized Clinical Trials: The Group Sequential Approach.” Biometrics 38:153–162.
Pocock, S. J., and White, I. (1999). “Trials Stopped Early: Too Good to Be True?” Lancet 353:943–944.
Proschan, M. A., Lan, K. K. G., and Wittes, J. T. (2006). Statistical Monitoring of Clinical Trials. New York: Springer.
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.
Schoenfeld, D. A. (1983). “Sample-Size Formula for the Proportional-Hazards Regression Model.” Biometrics 39:499–503.
Senn, S. (1997). Statistical Issues in Drug Development. New York: John Wiley & Sons.
Snapinn, S. M. (2000). “Noninferiority Trials.” Current Controlled Trials in Cardiovascular Medicine 1:19–21.
Wang, S. K., and Tsiatis, A. A. (1987). “Approximately Optimal One Parameter Boundaries for Group Sequential Trials.” Biometrics 43:193–199.
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.
Whitehead, J. (2001). “Use of the Triangular Test in Sequential Clinical Trials.” In Handbook of Statistics in Clinical Oncology, edited by J. Crowley, 211–228. New York: Marcel Dekker.
Whitehead, J., and Jones, D. R. (1979). “The Analysis of Sequential Clinical Trials.” Biometrika 66:443–452.
Whitehead, J., and Stratton, I. (1983). “Group Sequential Clinical Trials with Triangular Continuation Regions.” Biometrics 39:227–236.
Zhu, L., Ni, L., and Yao, B. (2011). “Group Sequential Methods and Software Applications.” American Statistician 65:127–135.