Reboussin, D. M., DeMets, D. L., Kim, K. M., and Lan,
K. K. G. (2000) Computations for group sequential boundaries using the
Lan-DeMets spending function method. Controlled Clinical Trials,
21:190-207.
Fortran program 'ld98' by the same authors as above.
DeMets, D. L. and Lan, K. K. G. (1995) Recent Advances in Clinical
Trial Design and Analysis, Thall, P. F. (ed.). Boston: Kluwer
Academic Publishers.
Lan, K. K. G. and DeMets, D. L. (1983) Discrete sequential boundaries
for clinical trials. Biometrika, 70:659-63.
See Also
Generic functions summary.bounds and summary.drift,
bounds to calculate sequential boundaries,
drift for exit probabilities given boundaries or drift (effect) or confidence interval given power.